PHENOM II 940 would be the better option if you just want it for gaming,
Its performance is better when it comes to gaming even though the
Intel core i7 920 would be alot better at other tasks,
BUT !! this is only if you are going to use a single graphics card,
if you plan to use 2 graphics cards in say sli for instance then the Intel core i7 920 will give you the better performance, strange as it maybe, but without going into to much detail the i7 920 takes better advantage of multi GPU set ups,
also the price of the motherboard and Ram would work out alot cheaper if you go for the PHENOM option, which then gives you more money to spend on a better Graphics card.
Now lets wait to see who disagrees with me LOL.