I have a 750i here and the spaces between the 2 pci-e slots leaves room between the cards so they can breathe. I imagine, but am not sure that you could use the upper and lower pci-e slots on the 780i....to get "breathing"room...??? 1 vote for the 750i I guess.
edit: check the boards out carefully to make sure you can plug everything else in you're going to need.
I like the 750i's price but it just doesnt compare with the 780i.... and With the EVGA, I wouldnt want anything except FTW because of it's capacitors.....Which cost's a lot compared to the standard 780i.
Im thinking about going with the XFX 780i. Good choice .vs. the other brands for $209 with a $30 mail in rebate?
EVGA 750i FTW because of its non reference design, capacitors, general quality and true x16/x16 SLI support.
If price is a really big deal to you, the MSI 750i Platinum is k, i mean the cooler is better than the FTW's, if a little invasive, but it runs sli as x16/x8 to the best of my knowledge. still great quality, but would probably bottleneck the second GTX 260. probably.
all depends on price and features.
BTW, from what i have heard, the ASUS is a POS, and the XFX is just reference design so..
I have Asus P5N-T Deluxe and 8800GTs SLi, very happy with it. PCI-E 2.0 Full x16x16 and triple SLi capable x16x16x8 and a fair few £ less than the 750i FTW (at least in the UK!) Fairly good overclocker too I've found, contary to some reports - have run 475FSB no problems...