Scott Ferris , Jul 26, 2012; 09:54 p.m.
What is wrong with the 50 you have as a portrait lens? I use mine a lot, if it isn't long enough for you the 85 f1.8 is, perhaps, even better then the 50 f1.4 and is reasonably priced. If that is too close to the 50 then the 100 f2 is a great "portrait" lens that is widely overlooked. If that is not long enough then the 135 f2L has an unmatched reputation as one of the greatest portrait lenses ever.
For landscapes nothing beats, or comes close to (with the possible exception of the 17mm TS-E), the TS-E 24mm MkII. Expensive but worth every penny and some.