I was always a huge proponent of Yahoo! It has pretty much everything that you can ask for, and it's FREE! There aren't enough additional features that a pay site offers to warrant the outrageous money they charge, imo.
I am however upset that Yahoo! offers a maximum of only 4 leagues per Yahoo! ID this year. It's a hassle to create another ID and to log in and out of your identities to be able to see your various leagues.
From Yahoo! help:
How many teams or leagues can I have?
You can create up to four teams in Yahoo! Sports Fantasy Football with a single Yahoo! ID. You can use these teams to join any combination of four leagues (Public or Custom; Head-to-Head or Fantasy Points).