Buying a PS3, what's the recommended model?

[Zman2k2]

So I'm replacing my old blu player with a PS3. Interested in some of the games, as my daughters' cousins now have a PS3, and they can game together online. My plan is to load the games on the HDD, and save the wear on the disc drive.

What's the recommended procedure here? Buy the 160Gig PS3 and swap in a bigger HDD later, or buy the 320Gig and stick with it for a while? Not really interested in Move, so probably will skip that option.

First purchases with the system are LBP and GT5.