Black, because it's cool. 16GB because my last three iDevices all had 16GB and I had plenty of room. Occasionally it will fill up, then I just delete all the crap I don't need. Right now I have 6 gigs free on my iPhone 4, with 400 apps installed. I don't store music on it, but my wife finds 16 gigs plenty for hers. Most media I just stream. I record lots of video, but don't store it locally. With iCloud there should be even less need!