Hmm this question keeps popping up and is always really hard to decide on
J;ME gets my vote as he is definetly the most versatile DJ on BT in terms of mixing styles and different genres.
Warmup, NRG, trance, classics, techno, all were balanced sets and definetly top drawer.
Best NRG DJ for me recently would have to be Dan Dyson. Mixing is faultless and is one of the most consistent DJs out there IMO 
Is going by individual sets there are loads. Todd P's sets I always keep an eye out for, as well as Narc's, Ben Frashiers', Ast and now there are way too many to mention 
Overall for me goes to J;ME. I like the way his sets progress nicely but does not play tracks just for the sake of filling the spot.