Title says it all, I imagine. What are the best transfers and trades that you can think of? Obviously it'll be a bit apples and oranges comparing across sports, so try and lay out why, and the landscape of the sport, in your answer.

A big one for us at Villa was selling Dwight Yorke to Manchester United. Looks a funny one at the time but because he was sold for what was a huge amount of money, that went a long way towards bringing in Dion Dublin, Paul Merson, Steve Stone, Steve Watson and Alan Thompson. We then went undefeated for 12 games and were top of the league until half way through the season. Couldn't sustain it but we finished top half for the next few years and basically rebuilt the entire side on the strength of one sale.

Another little strange one that I always thought was inspired was United picking up Henrik Larsson on a short term loan. He scored a few important goals in that spell for what I'm guessing was probably nothing but his wages.