I have answered these types of posts before and generally live to regret it, but here goes...

How much money are you willing to spend, what kind of film do you shoot, will you be scanning prints as well as film and what do you intend to do with the scans?

If you only intend to scan film then the cheapest dedicated film scanner will beat all flat beds (with the execption of the microtek duoscans).

If you only scan for contacts and the web then it realy doesn't matter much unless you shoot tranies and or B&W (and then only if your negs are pretty dense and you give a sh!t about highlight detail).