i second the firmware thing - my gf for a iphone 3g and she complains how laggy the apps are to open. She hits Contacts and the thing takes 4-5 seconds before she can scroll through her contacts.
the "genius" bar .. (or the idiot bar as i like to call them) told her its a product of the new 2.0 firmware/software -- its more resource intensive thus the lag.. he started talking about access times and crap too... i wanted to tell him that getting 5KB of data off a flash memory should not take 5 seconds.
The White is exclusive to 16GB (which I have) the 8GB are exclusively black, and the 16GB have a choice of White or Black. I chose white. I think it looks better and it doesn't show fingerprints like black does.