Even though I hate the Steelers, I guess Jerome Bettis would be a good one.
Echoing my beginning statement from above, Corey Dillon was a nice pick up for the Patsies.
Stephen Davis & Jake Delhomme made an impact on their SB run.
Being the homer that I am, Rian Lindell was a nice pick up. Unfortunately he hasn't had enough game winning opportunities.
That's about all that jumps out at me, in fact I can name more FA busts than good ones.