My three:
Sanath Jayasirya bowling over the wicket to Alec Stewart. The ball pitches at least 18 inches outside the leg stump. The umpire's finger goes up with the appeal.
England v West Indies - Trinidad 1998. West innings chasing 280 odd to win are in the 140s for 5 and have just lost a couple of wickets. England well on top when Fraser hits David Williams right in front. Steve Bucknor (IMO a very good umpire until late in his career) waves it off. Williams goes on to his highest Test score (and he only averaged 13 even allowing for this), puts on 100 with Caarl Hooper and sets up a win. With Ambrose in next had this been given England would have won that match.
Edgbaston 2005: Yes. Soon after Kasper comes in at no 11 he walks across his stumps and tries to play one extravagently over the leg side. It is dead LBW. Bowden (a bad umpire) watches the shot, not the ball, and gives it nt out. Would have saved a lot of stress