Well... Pro has more networking components, administrative tools, etc. It depends on what you're doing with it. Home is sort of stripped down for basic users.
I'm still fond of 2k pro. It may not be as flashy as XP, but as far as stability and security goes, I still used it for a couple years after XP came out. I know several business owners that still use it. XP did catch up eventually though, to be fair.
The processor choice is yours... I think they both make fine processors... I just prefer AMD for getting more performance for my money. If you ever want to toy with overclocking, I would also choose AMD.
Maybe in the next few days I can go through and see about a setup I'd recommend for you, if you're not in a huge hurry to get going on it.
Seabiscuit, check this out.
http://setiathome.berkeley.edu/forum_thread.php?id=33307
I'm really not sure what you're asking me about memory...