The only problem with Z77 boards right now is that if you install a Sandy Bridge CPU the last PCIe slot will not work. Until Intel comes out with an el cheapo Ivy Bridge CPU, your best bet if you wanted to use an Intel board is P67 or Z68.ASRock Z68 Extreme4EVGA Z68 SLI
← probably your best bet for maximum slots (three x16, three x1)
Other options if you can get them cheap:
Asus P8P67 PRO or EVO
Asus P8Z68-V or -V PRO
You still get 6 slots and if they are able to fix it down the road you get 7. Personally, I have 3 MSI H61m P21 boards with four slots each. Each one has a G440 and a mixture of ram. They can hold four cards each which, with any dual GPU is the limit anyways. The main benefit is I've bought them ranging from $45-59 brand new.