I will be purchasing my iPad 2 this coming weekend and plan to get the wifi-3g model with the AT&T network. I will only be using 3g while traveling but not sure how much data to purchase, 250 mb or 2g. There may be times when I will want to use GPS. But, mostly it will be used when no wifi is available while driving or staying in hotel with no free wifi. Does using GPS use up a lot of data for a 10-12 hour trip? Would 250 mb be enough for both GPS and web surfing and email? I have not been able to find that information if it has been previosly posted. Thanks for any information you can provide.