Burdines
It's a department store in Florida. ("
The Florida Store")
They sell all different types of cute bathing suits. My favorite type are Esprit bathing suits and Burdines has a HUGE selection from them. Their bathing suits are slightly expensive there (can run you $70 for something that can be completely ruined in chlorinated water) but Burdines often has great sales; they're infamous for their sales.
I don't like to catalog order my swimsuits. Swimsuits are one of those things that have to fit just right since they're not much covering you.

You don't want to accidently get a suit that too baggy, too tight, doesn't have enough material in places that there should be more material, or too see-through.
ETA:
If you like designer swim wear (Esprit, Nautica, Calvin Klein) but don't want to spend a lot, go to TJ Maxx or Marshalls. I've found some awesome CK, Nautica, and Esprit swimsuits there for $20!