opinion on CPU and advice for RAM

Hello all- I am a AMD guy and just need a little advice on an upgrade path I am thinking about. Before I go any further here are my current system specs:

Asus M2N-E Mobo
AMD 64 X2 5200+ OC'd to 2886Mhz
2X2GB Gskill DDR2 800 PI ram @ 4-4-4-12 1.95V
Sapphire Radeon 4850
480W PS

Ok- so here are my questions.
1. I just bought my Gskill DDR2 800 ram and love it. I am thinking of going to the darkside (Intel) and was wondering if that ram will work for a decent OC on either of 3 options: E8400, E7200, Q6600.
2. Which of my intel choices would you choose given that my ram will work, and with what MOBO would you suggest. I was thinking of DFI, but am a total noob to Intel and Intel OC's so any suggestions are more than welcome.
3. Should I leave it alone or do a cheap AM2 upgrade to a 5400 black edition and OC to somewheres around 3.4

any suggestions to do with 2-300 bucks is also welcome for ideas I have not thought of.


Thanks!

Thanks for the Info- I was actually just looking at that same mobo as I saw you replied- It says that the memory standard is DDR2 1200 though- are they all backwards compatible with DDR2 800? Im sure my ram can OC to 900 or so. May be a dumb question I suppose, but will and DDR2 work in a DDR2 MOBO? or is the standard the minimum. Thanks-