If you just want 250FSB, all those boards will do that, so then decide based on price, features, etc.
I'd probably go for P4C800 due to passive cooling and 875 chipset
Otherwise like I said they are all excellent. I'd also take IS7 v1.2 over AI7 since AI7 is the worst overclocker between all of these. When I say that I mean it wont reach 270+FSB like the others.