When I had the 85/1.8, I preferred the 135/2L ($900) on the 5D for portraits due to its better color and sharpness below f/4. Once I got the the legendary 85/1.2L II for portraits, I swapped the 135/2L for this equally-good 200/2.8L II ($660) because 200mm and 300mm are focal lengths I need more (I also have the 300/4L IS). In the end, I discovered that I needed only the 300mm, so I sold the 200L as good as it is.
The 200/2.8L focuses extremely fast and reliably, and it is very sharp at f/2.8 which is where I mainly use it. Close-ups look particularly good. The minimum focusing distance (MFD) of 4.9 ft. is like 3.3 ft. at 135mm, which is close enough to the 135/2L's MFD of 3.0 ft. With a 25mm extension tube, the 200/2.8L II's focus range is reduced to 3.2-5.9 ft. allowing for the same kind of extreme close-ups one can get with the 300/4L (MFD of 4.9 ft. * 200/300 = 3.3 ft.).
All in all, the 200/2.8L II looks, smells, and renders images exactly like the much-adored 135/2L but at 200mm f/2.8. If you like the 135/2L on a 1.6x crop body, you'll like the lesser-known 200/2.8L on a full-frame body (same FOV) because you can avoid the 1.4x TC on the 135/2L for action shots. I think the 200/2.8L II may even be slighly better than the 135/2L. That said, I don't think it's as sharp, contrasty, color-saturated, or versatile as the 300/4L IS. The 300L is that good. I sent the 200L in for calibration (which I have done with most of my lenses), and I think it's now about as good as it's gonna get, which is pretty darn good. I intended to use the 200L for indoor action shots and indoor performances where the 300mm is too long, but it turns out that I really don't encounter those situations right now. F/2.8 may, in fact, still be too slow for indoor action shots in dimly-lit gyms - a 1.6x crop body and the 135/2L may be a better choice in those situations. On the other hand, Canon has started releasing some camera bodies in 2007 (1DIII) that produce clean ISO 3200, which reduces the need for an f/2 lens.
The more versatile 70-200/2.8L IS is a notch lower in image quality and focusing speed, and much heavier (3.2 lbs.), expensive ($1700), and male-compensatingly conspicuous - I'd rather use the 85L and 200L/300L. The newer 70-200 f/4 IS ($1060) is actually sharper than the 200L and has IS, but losing an extra f-stop would be a problem for indoor action, plus it's almost twice as expensive. If you're willing to focus manually, the Leica R 180mm f/2 APO is supposedly the best lens ever made. The Canon 180/3.5L Macro is also excellent with great colors, but it's not fast enough in aperture or focusing speed for what I need in this range. The best auto-focus and widest-aperture lens in this range is the 200mm f/1.8L, which has legendary status. They are no longer made due to lead content (harmful to Canon workers grinding lenses, not to us lens users); $4000-$5000 on Ebay (original price was $2500); 6.6 lbs. Canon announced in October 2007 a new 200mm f/2L IS that is due out in April 2008, and this looks extremely promising, but it will cost $6000. I plan to upgrade my 300 4L IS to the 300 2.8L IS, which is the sharpest Canon lens ever.
I recommend the The-Digital-Picture.com
for comprehensive reviews.