Help figuring out a good second site?

[HentaiGaijin]

Currently I have an account with party poker. Play regularly, 1/2 and .5/1. I often clear bonuses and so forth. I'm looking to expand to a second site, to take advantage of additional bonuses. I'm fairly careful, try to do research into game quality, software quality, deposit/withdrawal capacity, etc. I'm considering either PokerStars or PacificPoker, but am generally unsure what makes a good set of criteria for a second site.

Any suggestions?