Another thing, the more complex the Apple product is the longer it'll be before something gets a new publicized updated version (apart from the technical changes that aren't advertised, manufacturing process, etc)
voice recorder, video recorder, cut and paste, downloadable / customizable ringtones, games and i'm sure i'm missing some others. Many of these have already been addressed by hackers so if that's what you plan on doing with your iPhone buy it now.
If you can get them onto your computer, you can sync them onto your phone through outlook or something similar.
As for the original topic, you can find almost anything you need through mods/hacks. So if you're confident with that sort of thing, I would get it now. From my experience there hasn't been many people disappointed after they bought it. The ATT store employee actually said the only returns he's had were people returning 4 gigs for 8 gigs, so I'd say the chance of you being let down are very slim.