The Canon EF 100mm is always a favorite. It's currently in my list of things to buy but I haven't bought it yet since I haven't had much time lately for photography. The 100mm version (as opposed to the 50mm) will let you get nice shots without having to be so close to your subject.

I'm a Nikon guy so take my advice for what it's worth. I don't have experience with these lenses but I can talk about it from a technical aspect. I would recommend the 50mm prime lenses over the 100mm for a few reasons: 1) 50mm lenses are much faster which means they will perform much better in low light situations 2) the lack of zoom actually makes it more of a general purpose lens so you can use it to take indoor portraits and group photos too. you'll find that a 100mm is not nearly as versatile 3) it's a lot cheaper. If you have the budget to get the f/1.4 I'd go for it. The f/1.8 are considerably cheaper but they also tend to feel cheap and the focus motor is louder as well. Someday I'll spring for a f/1.4 on my Nikon but I'm quite happy with my 50mm f/1.8 prime lens.