Well are there any that you like right now? Do you prefer arboreals or terrestrials?

Personally, I'd suggest something like a Grammostola pulchripes, because they've got a nice look, are big, generally pretty easy going and have fantastic appetites, not to mention ease of care. You could go for a GBB (Chromatopelma cyaneopubescens) - a little bit on the flighty side, but make amazing webs and look fantastic with their bright colours.

Really, you can go with any New World (and even Old World) if you're able to respect the individual animal and its temperament. It's all up to you!