Well, the Curve has GPS and it's $50 cheaper or something so I have my eyes set on it. It's very slightly thicker than the 8820, however it is smaller in LxW. Unfortunately that means a smaller screen, but eh.
http://www.sizeasy.com/
Really neat website for comparing the dimensions of objects, really well implemented. Can't believe I've never heard of it.
The Curve is basically the exact size of a 5G iPod it seems, while the 8820 is thinner larger.(more "smooshed")
It seems that the 8310 will fit better in my pockets, which is huge. Thanks for the help guys, I thought this was a dead thread!