I'm looking at buying MiFi to hook my iPad up to the internet when I'm away from home. It's a wifi-only iPad so don't have the option of getting a 3G contract and sim for it. However, the data allowance options are baffling to me. If I want to browse the net, check email, watch clips on youtube and download a few apps, how much am I likely to need? It starts at 1GB then 3, 5, 12 and 15GB. Any advice gratefully received!