After buying and selling a huge chunk of the Canon EOS lineup the final set that kept me totally content for a long time:
24-105L 100-400L, 24 f/1.4L, 50 f/1.4, 85 f/1.8, 135 f/2L, 300 f4L.
The 135 f/2L is one of those lenses that I experience "seller's regret" when someone asks me about it. It is outstanding! especially on a full frame 5D. On the other hand, the 85mm f/1.8 is probably the most value... not expensive.. good optics...
The lens lineup usayit references is basically hitting on all the "needed" focal lengths, with prime lenses at 24,50,85,and 135 that simply cannot be substituted for by ANY (and I mean ANY) zoom lens, regardless of price or exotic design. There is simply no equivalent for a 24/1.4, or a 50/1.4, or an 85/1.8 (except an 85 1.4 or 1.2, and even there....the 1.8 has several advantages,and the "value" usayit mentions makes both the Canon and Nikon 85/1.8 lenses better bang-for-buck lenses for most people), and the 135/2-L by Canon is one of the better "normal" primes I have ever owned. A 300mm f/4 lens equivalent can be had in a Sigma zoom,and a couple other zooms of very high cost, so that makes the 300mm f/4 prime lens basically a must-have for a lightweight yet still very high quality prime lens that is versatile (for use with a 1.4x TC and or extension tubes)
This is very interesting. I sold my 70-200L f2.8 IS due to it was soft at f2.8 on my 50D and now have the money for the 70-200 f2.8 IS II. But in the back of my head I have been thinking about getting the 135 f2 and 85 f1.8 instead. I"ve rented all 3 and its just a hard decision.
There are lovers and haters of both lens but I would rather the 24-105 due to the IS and longer focal length. At 105 and f4 you can get a fairly shallow DOF for a head shot or waist up. But it really depends on what you shoot...