TNG was the obvious choice for best overall but I really liked where Enterprise was going before the whole OMGXindi, it's action time derp. Just think of all the lore this series could have covered, they had the entire war with the Klingons, the Romulans and the neutural zone, the formation and rise of the Federation. All seen from the prespective of the crew on a very underpowered ship with nearly zero expirence.
Damn shame they felt the need to cancel such potential =(