I'm going with GFB G-force II, but each to their own. I just picked something middle of the range and can match my red lighting.
It comes down to appearance, size and function as well and it depends on where you're planning on fitting one. HKS has a really nice interface with more functions than most, as does Greddy Profec.
Just avoid any of the cheap Ebay ones unless you like seeing you engine internals become externals
Apexi AVCR. It's an oldie but a damn goodie and reliable. It has some extra features if you want to tune boost per gear too but I've never played with that function.