This is absolute bias on my part, and one of the few times I'll cop to preferring Horde over Alliance or favoring them. 99% of the time, I love both equally and play both equally, but I have to state this honestly and let the chips fall where they may: the Horde PvP gear at level 60 (with one exception) looked much better than the Alliance gear, and it deserves a return in some fashion or another.
It's true for just about every set, too, but I'll focus on the plate armor because that's what I was going for. I had just gotten my tauren to 60 before Burning Crusade was about to launch, the PvP system changed and honor became a currency instead of a ladder system. As a result, I really only had the time and interest to get the epic 2h sword, as you can see in the picture accompanying my first post here at WoWinsider. I was happy with that sword because it was the first really good weapon I'd ever PvP'd for. Well, the pig on a stick doesn't really count. I just got that to tide me over until I could get the sword. I did love it, though, you kind of had to, it was a big spiky pig head on a stick.