My impressions are from use, and from tweaking the files at 100% in post. I have no test equipment.
Probably the sharpest picture I have ever taken, was with an 85mm f/1.2 L, a landscape image at infinity focus (done manually via live view), closed to f/5.6. But at wider than about f/2.5, it wasn't all that sharp at any focus distance, and had severe vignetting even on my crop camera. Contrast was very good, color was nice with a lot of richness toward the violet end.
I've owned the 135mm f/2 for almost 4 years, it is extremely sharp even wide open on a crop camera. Some say it's not all that sharp, but it's possible there is some sample variation. It also has bokeh at least as good as the 85mmL, and with none of the "bokeh fringing" the 85 had (at least the one I tried.) It's possible the 135's bokeh is as good or better than the 50 f/1.2, I can only guess...obviously it's not as extreme in its shallow-ness.
I've rented the 500 f/4L (first generation), and the current generation 200mm f/2L. That 500 was not very sharp at all on my crop camera (no matter how I adjusted focus, or even if I focused manually via live view at 10x, on a tripod, on a motionless target...and was apparent via the live view's video feed, before I even snapped the shutter while the mirror was up). The rental place tested it, and found nothing wrong.
By contrast, the 200 f/2L was extremely sharp even on a monopod with its fabulous IS, and had better color than any other lens I've had experience with (including the 85L). The colors, well they looked like they were shot with a medium format camera! "Global contrast" was slightly more than my 135, which puts it at extreme. It didn't usually blow out highlights, though, so my camera's metering was still able to function well with it.
I've also tried the 300 f/4L and the 400 f/5.6L. The 400 was a lot sharper than I thought it would be...it was on par with the 200 and my 135. The 300 f/4L is certainly more than sharp enough at its price point...and I'm actually currently considering buying either it, or a zoom. I will never buy a long telephoto without IS.
The Zeiss 100mm Makro Planar f/2 that I tried, was extremely sharp via my crop camera, had extremely smooth bokeh (on par with my 135, if not exceeding it), and a color with very rich (almost over ripe) reds, but this was still pleasing and very usable. I wish I owned one. Some say it is the sharpest lens in the world, or was.
The Zeiss 35mm f/2 that I tried, was the sharpest wider angle lens I have ever tried. The color balance was very neutral, and the contrast was so extreme that its highlights overwhelmed my camera's metering, so I always had to under-expose a bit.
Another very sharp lens I've owned since Fall 2011, is the (Cosina) Voigtlander 58mm f/1.4 Nokton SLii, in Nikon mount, with a Canon adaptor. I refer you to photozone.de's test/review, and you tell me which they found to be sharper overall, the Canon 50mm f/1.4, or this one? (They don't admit it in their summation, but their test results speak for themselves...compare them side-by-side). It has some slight bokeh fringing at wider apertures, but is still very sharp wide open. Closed down a bit, it has to be one of the sharpest lenses ever made. It has almost no vignetting even wide open on a crop camera, and is extremely sharp to the corners, wide open...on a crop camera. No other f/1.4 lens I have ever tried, was capable of this. The color rendition is quite magical, in my opinion. Greens and reds are especially rich. The bokeh isn't the smoothest, but it's smooth enough for me.
I recall a magazine article, I think it was in "Digital Photo Pro" 2 or 3 years ago, where they recounted the sharpest lenses of all time. The sharpest they found, was a Leica 100 f/2.8 macro, which I believe ended production in the 1990's. From what I have read, the Leica lens I would love to own (and somehow use on an SLR without chopping it in half), is the 75mm f/2 Summicron Aspherical.