Which lens to complete the collection?

The 135/2 is pretty much the same weight as a 70-200/4 and just a little bit shorter.  The white thing is just in your head you must realize.  Most people don't even notice.  I carry mine all over and I don't notice anymore attention that if I had my 30/1.4 mounted. The only people who do notice are other camera geeks and quite frankly us geeks are going to notice a black Nikon 70-200/4 VR just the same as a white Canon 70-200/4.

Any of the Canon white lenses are amazing and I wouldn't want to miss out on using them over a personal hang up.  Does the 70-200/4 do what you need it to do?  If you want something to pair it with to have a larger aperture the 135/2 would be great.  Also the 85/1.8 is too good to not own unless you have the Sigma 1.4 or the Canon L.