I think PSPGo is not a good idea, IMO it's practically a downgraded PSP at a higher price. The only upside is that you aren't forced to buy a Memory Stick when you buy it. You can't sell games, trade in games, rent games, buy used games, etc. Nor get pre-order bonuses.
You can do everything that the PSPGo can do on the normal PSP, other than fight into jeans pockets (heck, barely anything fits into jeans pockets IMO), but it doesn't have built-in memory other than that bit of ram to save your username and settings.
And best PSP game is Monster Hunter Freedom Unite, if you and your friends have PSPs, you NEED that game. The game isn't that fun in single player though, but AMAZING in multiplayer (I think it's just as good as Halo, and I used to think that's not even possible).