The 50/1.8 is dirt cheap. Just pick one up and see if you like it. If not you can just sell it and lose maybe 20 bucks in the deal. Personally I don't use my 50 a lot on my 1.6x body, but for the occasions when I want a portrait lens it works great.
One thing to realize about wide aperture lenses is that the depth of field wide open is very narrow. This can give a nice effect in portraiture, but for lots of other subjects you may prefer to stop down and a slower lens may work just as well. If you have the bucks I think that the 17-55/2.8IS is a very nice general purpose lens for 1.6x Canon bodies, and the 2.8 with IS is often more useful for indoor shooting than the brute speed (and razor thin DOF of the 50/1.8 or 1.4). But it does cost something like 10 times the 50/1.8...