I'm also curious about changing the video card, but I'm glad to see that the hard drive and RAM are considered user-replaceable. Too bad it's still cheaper to buy the 8GB through Apple. 13" MBP user manual:
The manual only mentions that the drive must be a 2.5" SATA. There's a 250GB SSD for $900 at Newegg, which is the more than it is to upgrade from Apple (although you'd get to keep the 250GB 5400). There are some more affordable 128GB SSD drives, $250-300. However, they're just covered under a replacement policy, no refunds! So, it'd be nice to hear some first-hand anecdotal evidence about a particular brand working well. Or, better yet, which drives Apple uses as its OEM? I'm using just over 128GB now, and I'm not sure how much of that can be pared down just for the longevity and energy/heat/mass savings of a solid state drive.