Weellll...
Canon's 50 f/1.8 is...cheap. It's only what? 80-90 bucks right now? It's worth a lot more than that...but the lens itself is junk. The glass is really great, the body...not so much. It's got a noisy AF, and the manual focus ring is unusable unless you have chopsticks for fingers. Also, the aperture arrangement creates blown out pentagons in the background. Very distracting.
If you're interested in 50s...you should take a look at the Sigma 50mm f/1.4. That's the one I use, it's a beast. It's extraordinarily sharp...some say it's even sharper than Canon's f/1.2 "L" series 50. *puts on a flak jacket*...I've used the Canon f/1.2 and at the very best...there's little to no difference at f/2 +. At f/1.4 I'd have to say the Sigma is slightly sharper than the Canon. *hides*