It depends on what you need, and are looking for. Back in '04, I wanted to give the CR a try....just for two nights. But my dh and dd were underwhelmed by my choice. Well, after being there, they loved it. Said they had been completely wrong about the resort and wanted to stay there again. So...I just bought DVC, very small contract, at BLT.
GF? That's one resort I have absolutely no interest in. Not sure why. My dh likes it, but I think it's the 'snob appeal' for him. We have friends that say they will only stay there while at WDW...everyplace else is substandard!!
If you are going to spend the majority of your time at MK, then go with one of the monorail resorts. It's especially nice if there are younger kids with you ...sure makes getting back and forth much nicer.
But, if you will be spending equal amounts of time at the other parks, you may want to spend a bit less on your resort. We own at BW....but we spend a ton of time at Epcot. On the other hand, I love POP. Their transportation is the best onsite. I've stayed at POR, OKW, ASMusic, POP, BC, S/D, Polynesian, CR, BW...POP has the best all round bus system of the resorts I've stayed at.