i find that 50mm is abit too tight for cropped camera.
I'm using a 450D as well and have sold of the 50mm. Its just too tight for portraits i feel. Especially if u go for those gang-bang type of shoots where there are so many photographers which you just dont have the luxury of stepping back abit to get your field widen.
My recommendation would be a Sigma 30mm F1.4. Aiming for that piece of glass now.