which mobo would you buy? and why.

Anandtech awarded the IS7 the "editors choice award". You can see a full board comparison at their website.

I'd go with either the IS7 or P4P800. No, I don't think the added features for the -G or Deluxe are worth the added expense, but they may be worth it to you.

I prefer the outputs on the IS7 over any Asus board, but the P4P800 has an internal joystick header which I would also like to have (I have a super awesome joystick).

<font color=blue>Watts mean squat if you don't have quality!</font color=blue>