Wow ..... $345 for R2E and $380 for R3E here in US of A.
About the only advantage I can see for the II is the daughter card (Supreme X-Fi). The reviews on the R3E have been astounding and new OC records were set with it and THG's recent event. Tho I can say I really don't need to adjust my BIOS settings from my iPhone (BTW.... I don't have an iPhone......using a 5+ year old Treo 650).
I really appreciate the boards OC profiles feature but the features on this board are just so extensive, I can't see using half of them.....The 1st review I read on this thing was 26 pages long.
I was kinda wowed by the 222 BCLK and the lower voltages it was able to maintain stability at. I did a R2E build in October and if I was to do it again, I'd use the R3E ..... tho I'm likely to wait till mid to late summer to allow hardware and BIOS etc to mature a bit.
The R3E will require you to buy a specific case with 10 expansion slots (something like a thermaltake xaser VI or the lian li pc 80) because of its dimensions which are similar to an EVGA 4X SLI classified.. The R2E can fit on any regular ATX cabinet with 7 expansion slots.. This is just for info as i guess $$ is really not much of a concern for you.. So in this regards, the R3E gets the obvious vote.. Though personally, i love that EVGA board..
From what i have learnt unless i do 4 way crossfire i won't need 10 expansion slots. I May do 3 way 5850 and a 9800gt or maybe just a 5850 crossfire and 9800gt for phsyx
From what Ive learned creating a fourm on Physx, your 9800gt will be almost useless unless you play the FEW games that actually ustilize physX. I though most games use it automatically when in fact the game has to be liscensed by Nvidia. I previously didnt know this... so I guess that 3rd card would be a waste of space or use more of your PSU if you plan to use physx for games, if you have apps on the other hand that utlilize physx...(i dont know any).
Why not go the SLI route with the GTX 470.. That way you get physx (for whatever importance it is) without needing the 9800GT.. The antec 1200 features 7 expansion slots so getting it for the R3E is wasting money one way or the other..