I wasn't that impressed with my 70-210 f/4 zoom either so I sold it.
I had a 28 f/2.8 but the 28 f/2 really is better for wide open work -- if you are always stopped down to f/8 or so then the f/2.8 version is fine.
Never owned the 35mm f/2.8 but the f/2 version really is that good, it deserves all the praise it gets.
24mm f/2 is another great one.
50 f/1.4 is still soft until you stop it down a fair bit. The f/1.8 is actually sharper in my experience though colder and without as much contrast or saturation.
200mm f/2.8 is very good. 300mm f/4L is good but really not that much better than the 300mm f/4 version.