So here are the top 20 lenses based on user ratings with no regard to cost:
Rating
1 - Canon EF 85mm f1.2L USM Mark II
2 - Canon EF 500mm f/4.0L IS USM
3 - Canon EF 300mm f/2.8L IS USM
4 - Tamron SP AF 180mm f/3.5 Di LD IF Macro
5 - Canon EF 135mm f/2.0L USM
6 - Canon MP-E 65mm f/2.8 1-5x
7 - Canon EF 35mm f/1.4L USM
8 - Canon EF 85mm f/1.2L USM
9 - Canon TS-E 90mm f/2.8
10 - Canon EF 200mm f/2.8L II USM
11 - Canon EF 600mm f/4.0L IS USM
12 - Canon EF 200/1.8L USM
13 - Canon EF 70-200mm f4.0L IS USM
14 - Canon EF 400mm f/2.8L IS USM
15 - Canon EF 100mm f/2.8 USM Macro
16 - Canon EF 70-200mm f/2.8L IS USM
17 - Canon EF 400mm f/5.6L USM
18 - Canon EF 100mm f/2.0 USM
19 - Tamron SP AF 90mm f/2.8 Di Macro
20 - Canon EF-S 17-55mm f/2.8 IS USM
The first thing you'll probably notice is that the top 18 out of 20 are Canon lenses. The other two are both macro lenses from Tamron.
The second thing you may notice is that the top 12 lenses are all primes, and overall 17 out of the top 20 lenses are primes. The highest ranked zoom is the 70-200/4L IS and it's quite moderately priced among this competition. A new entry to the list is the Tamron 180mm macro. Note that there are only 10 reviews so far, so the statistics aren't as strong as for a lens like the 70-200/2.8L IS which has been reviewed by almost 240 users.