I'm using Tor-browser-bundle with Vidalia. Yesterday, just out of curiosity, I clicked on "view the network." In the "connection" box, I see my circuits. About 5, 6 circuits each with 3 different nodes. Then I realised something : only the 2 last nodes are different, the first is always the same IP. So I click on "new identity" and guess what ? Same first node again. Exit node have changed, very well, but the first relay is the same.
Is that how it's supposed to work?