Well, I will have to confess that on occasion I go for the Cell Tech Creatine. You can usually find it on sale somewhere anyways. It tastes pretty good which counts for something. Granted you are probably paying for the name, but if the few $ doesnt really matter then who cares. I have had as good results with this as with any creatine.
The other creatine I use is just plain GNC mono powder, mix it in to the post workout shake.
I actually cycle creatine on and off about every other month though and find this works better for me than just taking it constantly.