I am not sure if this is a recent development or what but today I was going to pre-order my vita but I noticed Gamestop, Amazon, and Best Buy seems to have changed their listings. Now the 3G version in the "Launch Bundle" guise comes with a 8 gig memory card, AT&T Data Connect Pass, and a PSN game at still $300 bucks vs. the $250 for the bare bones wifi model.
If your interested in picking one up the 8 gig card alone is $30 and with the news that you won't have to sign up to any AT&T yearly contract but rather pay-as-you-go I don't really see a reason to go with the wifi model over this.
http://www.amazon.com/PlayStation-Vi...8319950&sr=8-1
http://www.bestbuy.com/site/Sony+Com...&skuId=2095647
http://www.gamestop.com/ps-vita/cons...productDetails