Cryptsy is by far the best for what you want (and highest altcoin trade volume/selection). Bter is another option that I used regularly, and I wouldn't risk by sending lots of coins to most other alt-exchanges. I also tried Coins-e (very low trade volume) and coinedup (only because it had selected coins I was interested in). The latter has login/authentication system linked to your google account, probably a bad thing.
I didn't really use Vircurex, but it seems legit.
Vircurex is faster, and works better for mobile trading. However you get better prices on Cryptsy generally.. But for what it's worth I'd have to go with Vircurex. Far less hassles (money disappearing, etc..)