I have used Gigabyte and Asrock recently.
Gigabyte are my preferred board of choice, however if there was a good deal on an Asrock I would definitely consider it.
I am pretty much in the same boat as you and have decided after pricing up that a new PC with probably a sandy bridge chip for a start works out much more viable than upgrading my AMD set up.
I'm going to wait a while for reviews though as it may pay to go with a Z68 board and Sandy bridge if they are cheaper. I figure there may be price drops ?
I don't really know what the main advantages of the new boards are but I am keeping options open at the moment even though I do feel that I will end up with a fully featured Z77 or Z75 board.
just depends on reviews really.