I don't like Gigabyte boards. They always get good reviews (bribes?
), but I've never been impressed with them. I've used 3 Gigabyte boards in the past 2 years and all 3 had annoying minor issues that took me a few days to resolve after I built them.
My picks would be Asus, Abit, and sometimes MSI.
Abit boards are typically the best overclocking boards, but they have their faults. They tend to use fans to cool key motherboard components, which unfortunately tend to fail after about a year. (It also adds noise.) In the past they were also known to use poor quality capacitors. Asus boards are typically very well built and are usually the fastest boards at stock speeds, but they aren't quite as good for overclocking as Abit's boards. They are also the most expensive. MSI boards are simply a good value.