Pretty normal to me. Especially with an aluminum case which transfers heat more than glass. It's basically a mini computer in your hand, it's going to get hot with extended use.
I used about a gig of data with my 3GS a month. The 3 days I've had my 5 I've used just over a gig. Of course I'm playing with it more but I'm doing things I wished I could do on my last one. So glad I have unlimited!
Anyone have a problem with maps that after scrolling around for a minutes or it becomes extremely lagy to the point where it's unusable? I have to close the app completely to get it to stop.