If you are coming from a film background then theres a few things you can do but if you'v only ever had digital then the simple answer is get yourself EF 50mm 1.8.
There are afew ways to use an fd lens on the new cameras....
--use an adaptor without a glass element inside it, you will lose no quality since its the same as attaching the lens directly to the camera but since the distance from the lens to the mirror is wrong you will lose out on infinity focus, if you rotate to infinity on the lens the furthest thing in focus will be afew feet from you at the most. Also since there are no electronics you lose aperture control and have to do that manualy as well as focus yourself. They make great macro lenses as you can be afew inches away from the lens and still get stuff in focus.
-- Use an adaptor with a glass element inside, you will lose a fair bit of quality and the quality will only be decent at f4 to about f11, again manual focus and manual aperture control. You will get infinity focus. There are some high end adaptors made by canon but they will cost some serious $$ and thats if you can even find one, I'v never seen one for sale and I keep an eye out.
-- Convert the mount or get someone to do it but not worth it for a 50mm 1.4 maybe for a 1.2. Remove the old FD mount and machine an EF mount onto it. difficult to get right is an understatement. I have done afew but I havent got time right now until I get into video more and then I'l do some for video work (see my flickr).
Heres a FD 28mm 2.8 converted to EF, full aperture control as well as infinity focus
attached to my camera..