Update: Tails moved to uBlock Origin.

###tl;dr version:

Tails uses uBlock Origin, if you use the same version, lists and config as Tails you can block most ads and keep a reasonable anonymity set, or you could just use Tails.

###Longer version:

Ad-blocking is fingerprintable.

Disabling javascript will not stop it being fingerprintable, an observer can still watch the resources you do or do not load. An adversary can craft a website to enumerate blocking from common lists to determine which website elements you do or do not load, and thus which lists you subscribe to. Using less common lists or special lists will make you stand out further.

Tails ships with uBlock Origin in it's Tor Browser (something that no other answer actually touches on?). If you were to use Tails' uBlock Origin version, lists and configuration you would appear like a Tails user, which would give you a reasonable anonymity set.

Ad-blocking is censorship, you allow third parties to define what you can or cannot see on the web.

Ad-blocking does not defeat tracking. If you subscribe to every list in the world, you will still be subject to tracking because blacklisting never works with 100% efficacy. You should not approach ad-blockers in the belief that they make you less trackable, instead they should be approached as a means to improve your browsing experience if you (like I do) find ads offensive.

###Further suggestion: The Tor Browser should ship with a default ad-blocker. They have legitimate reason to not want to allow some third party to provide a text file that says what will or will not load on the internet for their users. However, that being said people want ad-blockers (not all people all of the time but some people some of the time) and the Tor Browser not shipping with something like ABP or uBlock means that more people are likely to just install some ad-blocker and configure it themselves. This is, ultimately, fragmenting anonymity sets. I feel the Tor Browser should ship with an ad-blocker, with a sensible configuration, that is disabled by default. This would allow users who are going to install one anyway, to be a more homogeneous set.

Update: Tails moved to uBlock Origin.

tl;dr version:

Tails uses uBlock Origin, if you use the same version, lists and config as Tails you can block most ads and keep a reasonable anonymity set, or you could just use Tails.

Longer version:

Ad-blocking is fingerprintable.

Disabling javascript will not stop it being fingerprintable, an observer can still watch the resources you do or do not load. An adversary can craft a website to enumerate blocking from common lists to determine which website elements you do or do not load, and thus which lists you subscribe to. Using less common lists or special lists will make you stand out further.

Tails ships with uBlock Origin in it's Tor Browser (something that no other answer actually touches on?). If you were to use Tails' uBlock Origin version, lists and configuration you would appear like a Tails user, which would give you a reasonable anonymity set.

Ad-blocking is censorship, you allow third parties to define what you can or cannot see on the web.

Ad-blocking does not defeat tracking. If you subscribe to every list in the world, you will still be subject to tracking because blacklisting never works with 100% efficacy. You should not approach ad-blockers in the belief that they make you less trackable, instead they should be approached as a means to improve your browsing experience if you (like I do) find ads offensive.

Further suggestion:

The Tor Browser should ship with a default ad-blocker. They have legitimate reason to not want to allow some third party to provide a text file that says what will or will not load on the internet for their users. However, that being said people want ad-blockers (not all people all of the time but some people some of the time) and the Tor Browser not shipping with something like ABP or uBlock means that more people are likely to just install some ad-blocker and configure it themselves. This is, ultimately, fragmenting anonymity sets. I feel the Tor Browser should ship with an ad-blocker, with a sensible configuration, that is disabled by default. This would allow users who are going to install one anyway, to be a more homogeneous set.

###tl;dr version:

Tails uses ABP, if you use the same version, lists and config as Tails you can block most ads and keep a reasonable anonymity set, or you could just use Tails.

###Longer version:

Ad-blocking is fingerprintable.

Disabling javascript will not stop it being fingerprintable, an observer can still watch the resources you do or do not load. An adversary can craft a website to enumerate blocking from common lists to determine which website elements you do or do not load, and thus which lists you subscribe to. Using less common lists or special lists will make you stand out further.

Tails ships with AdBlock Plus in it's Tor Browser (something that no other answer actually touches on?). If you were to use Tails' AdBlock Plus version, lists and configuration you would appear like a Tails user, which would give you a reasonable anonymity set. (Tails is looking at moving to uBlock Origin)

Ad-blocking is censorship, you allow third parties to define what you can or cannot see on the web.

Ad-blocking does not defeat tracking. If you subscribe to every list in the world, you will still be subject to tracking because blacklisting never works with 100% efficacy. You should not approach ad-blockers in the belief that they make you less trackable, instead they should be approached as a means to improve your browsing experience if you (like I do) find ads offensive.

###Further suggestion: The Tor Browser should ship with a default ad-blocker. They have legitimate reason to not want to allow some third party to provide a text file that says what will or will not load on the internet for their users. However, that being said people want ad-blockers (not all people all of the time but some people some of the time) and the Tor Browser not shipping with something like ABP or uBlock means that more people are likely to just install some ad-blocker and configure it themselves. This is, ultimately, fragmenting anonymity sets. I feel the Tor Browser should ship with an ad-blocker, with a sensible configuration, that is disabled by default. This would allow users who are going to install one anyway, to be a more homogeneous set.

Update: Tails moved to uBlock Origin.

###tl;dr version:

Tails uses uBlock Origin, if you use the same version, lists and config as Tails you can block most ads and keep a reasonable anonymity set, or you could just use Tails.

###Longer version:

Ad-blocking is fingerprintable.

Disabling javascript will not stop it being fingerprintable, an observer can still watch the resources you do or do not load. An adversary can craft a website to enumerate blocking from common lists to determine which website elements you do or do not load, and thus which lists you subscribe to. Using less common lists or special lists will make you stand out further.

Tails ships with uBlock Origin in it's Tor Browser (something that no other answer actually touches on?). If you were to use Tails' uBlock Origin version, lists and configuration you would appear like a Tails user, which would give you a reasonable anonymity set.

Ad-blocking is censorship, you allow third parties to define what you can or cannot see on the web.

Ad-blocking does not defeat tracking. If you subscribe to every list in the world, you will still be subject to tracking because blacklisting never works with 100% efficacy. You should not approach ad-blockers in the belief that they make you less trackable, instead they should be approached as a means to improve your browsing experience if you (like I do) find ads offensive.

###Further suggestion: The Tor Browser should ship with a default ad-blocker. They have legitimate reason to not want to allow some third party to provide a text file that says what will or will not load on the internet for their users. However, that being said people want ad-blockers (not all people all of the time but some people some of the time) and the Tor Browser not shipping with something like ABP or uBlock means that more people are likely to just install some ad-blocker and configure it themselves. This is, ultimately, fragmenting anonymity sets. I feel the Tor Browser should ship with an ad-blocker, with a sensible configuration, that is disabled by default. This would allow users who are going to install one anyway, to be a more homogeneous set.