I realize this is not cutting edge (2 years old) and that I have mentioned the presentations before, but with the transient nature of a blog's readership, it is worth mentioning again! And besides, I want my class to watch at least one of them! All are from the FMA 2003 conference and are available at FMA Online.
Aswath Damodaran and Tim Opler on valuation. They are excellent!
I guess I like Damodaran's a small bit better, but if you have time, watch them both! (He also has Powerpoint slides)
Short version: DCF is theoretically preferred, but most use market multiples and comparables because they are easier, faster, and less sensitive to assumptions. Moreover the analyst assumes much less risk using the market based models than (s)he does using personal assumptions necessary in DCF based valuation models.