I've seen tons of bad football matches. Worst I've been to was probably a reserve game against Blackburn where it was below freezing, the pitch had turned into a mud bath and neither side had a shot on target. Literally nothing happened.
As far as other games go, the one that always jumps to mind is the 2003 European Cup Final. That thing was just atrocious for such a hyped game. The United vs Villarreal games in Europe were dreadful too ... we've played them four times and neither team has ever scored against the other!