there's always yahoo. not the best, but hey! it's free.
Yahoo's pretty good and free (for now...). Yahoo's the best free FF site IMO. For pay sites, Cbssportsline is not too shabby. ESPN is okay along with NFL.com. I like sportingnews.com's draft program (way better than Yahoo's crappy java based, dull-colored draft program).
Just look around for a while (there are lots of FF sites) and see which fits your needs (keeper league, salary league, etc. ) and budget.