I like Gigabyte motherboards, a lot of other people like ASUS. They are both quality, reputable brands.
I'm very new to overclocking the "i" processors. I've built 3 machines using Gigabyte motherboards and i5-750's. I managed to get between 3.8 and 3.9 GHz to stay stable in stress testing on all 3, and I didn't spend a lot of time adjusting settings. All 3 of those machines were for our office so I set them down to 3.5GHz and they run 24/7.