I'd Vote Poker Stars for a couple or reasons:
1) They sponsor this site... if you sign up using this link:
http://www.pokerstars.com/?source=chiptalk.net, chiptalk gets a little grease
2) The last two winners of the WSOP got their seat through pokerstars, and if remember correctly, at the final table.. think over 50% of the players had won a seat through pstars.
3) Cheap, they have $2 super satelites, $33 satelites, and $160 double table shootouts (those sound cool , you win your table and you win the second table (which are winners from 8 other tables). You win a seat at the WSOP. They also offer tournaments for free with their frequent player point (FPP) program.. see here
http://www.pokerstars.com/2005wsop/diagram_fpp.html
4) That is where the offical chiptalk tournaments are held, so if you have an account, you can join the fun on thursday nights... see this thread...
http://chiptalk.net/forum/viewtopic.php?t=1187
