I have a badass mono green I call "Green does everything (except direct damage)."
Basically, it has aggro, combo, mana ramp, and lifegain all rolled into one 60 card deck. Got some Baloth's for aggro, everything's beefed up by a Leyline of Vitality, so I gain life every time I play a creature, too. Several Khalni Heart Expiditions combo'd with Grazing Gladeheart for lifegain off of the mana ramp. Then we of course have the Protean Hydra who becomes basically un-killable when combo'd with the Leyline, and then you put Canopy Cover on him, and just win the game.
But yeah, I used to like blue a lot, but I'm not a big fan of counter-magic. I just feel like too much of a dick, and I can't get used to leaving 3 untapped lands every turn...