Which expansion overall had the best looking tier sets?

[Vaelorian]

TBC without question!

That's the answer for every, "Which expansion had the best, ___________?"

While I respect your opinion I just don't share it. TBC had almost everything the best. Sure I agree with that. Raidwise (heroic) were far more kickass in Cata Tier 11 and perhaps 12. TBC did not have heroic raiding apart from (if you can call it that) Sunwell. Though, I did have a lot of fun, a lot of fun during TBC. Probably a lot more then during Cata's raids.

I have a hard time choosing between TBC prenerf heroic 5 mans (the first month or so it was very hard) or Cata's heroics prenerf. The Cata ones were shorter in lenght. So I'll probably choose TBC for better heroics.

[Dr Perry Cox]

I selected TBC. I mained a Hunter and Druid at the time and loved the gear. Never played Vanilla, but after seeing MC and other sets, I was not as blown away as I was in TBC.

[l33t]

TBC, because sets were designed around classes, which gave us absolute badass items like warrior/priest/paladin/druid/etc t6/t5...

Of course we get some nice designs that fit classes even now (paladin's current tier, lock's pvp set), but in general sets are designed around environment, which leads to overall blandness and likelihoodness (warrior's latest tier as an example, there is absolutely zero "warrior"-ity in it, you may as well name it DK's or even rogue's set and noone would care).