I saw the Verizon vs. AT&T data plans on TUAW I think this morning. verizon had 2GB for 14.95 I believe which they said was 4x that of AT&T offering (Verizon better). We have 2 wifis. Bought. palm Pre Plus last May with free mobile hot spot (which is why we bought it--2 yr contract) so use it when needed which is really very rarely to be truthful since we have so much free wifi availble around here. Not everywhere may have that. The Palm can connect up to 5 devices though speed will drop as I understand it with each device added. We have often had 2 hooked (my Touch usually because I forget to chosoe not to look for network) and one of our Ipads. We have a GPS already so that wasn't important but even there I don't use it much and actually prefer to use maps and plan a route since I find GPS often chooses routes I don't like LOL. I find I mostly use the hot spot when we are in an area looking for restaurant or need local directions, something similar. I still am not sure what I'll do when I buy next tablet (probably gen 3) since this has worked so well. I think it will depend upon data plans available, price of tablets and whether we prefer a hit spot on a phone.
Here's the link to the chart with Verizon and AT&T data pricing