I like Asus. They are kind of the Toyota of motherboards. Not necessarily the ultimate performer, but reliable and long running...although the Asus P5K has premium performance also. Asus is by far the top selling motherboard, nobody else even come close.
I have the P5K Deluxe, (which was included in a new pre-built computer I just purchased, which came with a E6850, 250g hd, 2G 6400 ram, Antec ps, aluminum Thermaltake case, ATI 256mb and Vista Premium disc, for $500, in craiglist, brand new!) Most pundits would suggest going for the P5K Premium, but if it were my money, I would get the P5KC (not for the DDR3, but because it seems much like the Premium, rather than the P5K vanilla for the same price). Being a cheapie I would probably go for the P5K SE, (just as long as it is an 8-layer board like the Deluxe/Premium). Check it out.
I sold the E6850 on EBay, but with the P5K my trusty old E6300 runs at 500FSB (x 7 = 3.5GHz) on 1.3875v and is way cooler than my old P5B. Although this E6300 did reach 533FSB x 7 (100% oc on air, non-modded) on my P5B vanilla...and ran 24/7 at 470FSB (x 7 = 3.3GHz) with stock 1.3125v.
I haven't tried a maximum run yet with my P5K Deluxe, as I also installed another 2G of Crucial Ballistix for $44 from NCIX (but which lowered the default timings from 5-4-4-15 to 5-5-5-15, at the same voltage?) so I don't think I could oc as high with 4G as with just 2G (Crucial 10th Anniv. which ran at 4-4-4-10 at 1066MHz with only 2.1v on my P5B).
Not sure about those other boards. Some are cheaper...but? I had a Gigabite 965 for one day, then took it back (it was more like a Suzuki than a Toyota...). I would always buy Asus, and you won't be dissapointed with the P5K.