What was your favorite power set in the whole game and why? Yes, you can only pick one!!
For me, I think it would have to be [Gravity Control]. No, it wasn't the strongest set, no it was never a FotM build or a star at PvP, and nope, you sure couldn't farm with it... but the shear variety in the set made it interesting to me to play, and especially after they changed the single target bubbles to AoEs, and made Dimension Shift into an intriguing situational power. Perhaps my favorite thing was when I discovered a new niche for one of my powers, or an interaction I didn't realize was there. For instance, remember the part of the MoM trial when you had to get little old Penelope to stand in the center of a collapsed Storm otherwise she was invulnerable? Enter Wormhole, and you can merely pull her to the first room and place one of those storms on top of her every time... it was great and had better base accuracy than TP Foe, IIRC. Also, it was pretty cool that the AoE Immob didn't interfere with KD powers... so one could use it pretty much willy-nilly even over an Ice Slick and not nullify the power.
But, mostly, I loved it because it was the set used on my main, so I used that set for hours upon hours. I lead probably hundreds of badge runs with a Gravity Troller on Justice, and had somewhere close to 1300 badges on him too. Warts and all, I learned to love that set.