This is a fairly short list, though I do admire what some folks have put together. In general, I admire what they've accomplished, not necessarily who they are.
I have no idea who this guy really is, and I never really faced him in PvP. What I do know is that he was one of the most feared rogues on Malygos - and it didn't matter which side he was fighting for. His legend carried into BC, and those rogues in Shadow Labs that would one shot your healers were named Mido in his honor. To put it bluntly, if Morores had been Mido - he wouldn't have needed four henchmen to take down a raid. I don't know where Mido is now, but I tip my hat to that level of gameplay.
Legs and Cranius
For those that don't know Cranius, well, let this be a brief introduction. Cranius is the voice behind Big Blue Dress, The Lament of Captain Placeholder, and others. Legs does the machinima work. Together they create some amazing videos, and I admire that. While I certainly which Cranius would release more, I can appreciate that it probably doesn't pay very well, and doing all that video capture and editing has to take time.
I don't know Matt over at World of Matticus, but I do have a lot of respect for him. He runs a fairly successful progression raiding guild, that has a decent PvP arm as well. He maintains World of Matticus, maintains Plus Heal, and is involved with a few podcasts. While I don't always agree with his opinions, I do have to admire the fact that he keeps it all held together. Even if there really are a string of people in the background working on it to keep the whole thing floating, I admire the ambition.
That's about it
It's tough for me to admire someone regarding the game, especially when I don't even admire a lot of folks in general. I might admire their gumption, or ability, but as a person? It's tough. One of the men I admired most in my life died on Easter morning this year. My uncle succumbed to a second fight with cancer after beating it for a bit last year. He was 79 years old, had cycled across most of the world, and could spin a tale with the best of them. After admiring a man like that, it's hard to follow someone else.