I won't be getting an iPhone until mid-May. But when I do, it will of course have a data plan. If I buy an iPad now, do I need to buy a separate data plan for it, or could I wait until I have the iPhone and "share" the iPhone's data plan between them? If I would need to have two separate data plans for each device, that would be the deciding factor in which model iPad I purchase (just wifi or wifi + 3G)
Or you could do what a lot of users do - get a tethering plan for their phones and use a wifi-only iPad to connect to it.
I don't have a smart phone, but have an ATT iPad 1. I had activated it for two months when the pad was new, to see how well it worked (it worked well) then cancelled the plan. I'll turn it back on at some point this summer when I'll be away and not have much wifi available, then cancel again. Most of my usage is within wifi range.