This is an interesting website....
http://www.wlcastleman.com/equip/reviews/index.htm
and especially this:
http://www.wlcastleman.com/equip/reviews/50mm/index.htm
Basically, from this website the potential buyer could obtain a good and unbiased information on various lens performance (Canon only).
Also, this could be interesting as well:
http://forum.ourdarkskies.com/index.php?showtopic=5151
According to all above, it seems that Canon EF 50mm f/1.8 II is a very good choice, with excellent price/performance ratio :-)