Who is the best? At what time of year? On what products? Against what opposition?
I'll list them in my order without really touching on the Clinic implications.
1. Contador. Day in, day out, he's the best. You cannot be as dominant as he is without a ton of natural talent. Say what you want in the Clinic, but he's consistent all the time and cycling is getting cleaner and slower in the last year or so. If everyone raced clean I have no reason to suspect he wouldn't win all the time like he does now.
2. Andy Schleck. Week in, week out, he's crap. LA type rider. Do I naturally think he's marvelous? Nope, I think the Clinic answers most of his performances. Last years Tour he was on par with Contador, which for him was a HUGE improvement. A month or two nefore at the ToC he was crap. He's the best of the rest when trying, which is usually only at LBL or the Tour. Plus, he's better by quite a bit when he goes hard than everyone bar AC.
3. Valverde or Samu. Good all the time. I think the only guy with a hope in hell of beating Contador overall is naturally going to be an all rounder. My vote goes to Valverde.
4. Anton or Rujano. Majestic, cool and damn awesome when on song. In the hills, they're amazing.
5. A diesel. Which means I have to tier them from here on out and pair them with like riders.. But consideration must be given to where people race (parcours) and who the opposition is. Meaning Evans comes first here. Good everywhere against everyone. He'll make the Tour podium this year.
First bracket: Nibali and Basso. Both have won a GT in the last 12 months, Vincenzo has matured a ton since last years Giro. He's second to Contador at the Giro right now and has some solid climbing efforts to his name. Ivan outlasted everyone at last years Giro. Enough said.
Second Bracket: Menchov. He came third at last years Giro and is strong over 3 weeks. He'd dangerous. Scarponi. Can't put him ahead of Basso, but he's damn consistent. Should be higher actually. Forget his placement. I rank him up there with Evans.
Bracket 3: Gesink and Jurgen Van den Broucke. Obvious reasons, they were fighting for a top 5 in last years Tour. Franck Schleck. He's about where these two are, that is when he doesn't fall down.
Bracket 4: Kloden, maybe Horner. Obvious reasons, both do well enough all round all year round. Have shown climbing prowess at Giro's and Tours in recent years. Only the Shack race the ToC hard. If Horner turns up at the Tour and blitzes everyone, his claims will stand. He won't. It would SCREAM DOPER! Levi couldn't beat Mick Rogers at last year ToC. Enough said. There team is in enough trouble.
Bracket 5: The rest, Kreuziger, Hesjedal, Vande Velde, Vino, I guess even throw in Nieve and Gadret on that list. Bottle can make this list and Rodriguez. They do well enough, but lose big time sooner or later, often in chunks on multiple days. Top 10 is a possibilty, even a stage win, but they ain't the poster boys for dancing on the pedals.
The list and requirements on how to rank climbers is huge. It's best to look at the parcours. Nibali ain't the best up steep climbs, but he can pace himself and come back. Meaning Rujano or Anton might get in a break, but they pay for their effort. Nibali gauges his efforts because his physiology isn't as suited to blasting up mountains and overall makes more time, advancing him on GC. Place the parcours in context with the race. Example, the Ardennes, Gilbert should make this list, but we all know how good he is in a GT. Short, steep climb at the end of a long stage, he's damn near unbeatable. Should this not rate? In the proper context, yes, which is classics, in a GT, not really. He's arguably not even Climbing jersey material, but the man has his moments in the hills, not the mountains.
NOTE: The top list, the one's I didn't Tier, I consider to be natural climbers. They make climbing look easy. The rest either have a sharp punch, Rodriguez, are pure Diesels, or look like pure climbers, but never seem to gap the diesels like the first group can. A guy in the second Tier can beat one of the top group who isn't AC, if and only if they are consistent all round. Lose timem but only a bit in the hills, make it back in their chrono. Andy Schleck can be beaten this way.
Oh and Dim. Horner is not the second best climber in the world. Anton or Samu is after Andy Schleck. If Ricco were riding, I'd give it to him. Consistency will get you a GT, but not necessarily onto my list of worlds best climbers. I like the people who slug it out, but climbing is meant to look good. Gotta do that to make the list.