Wow the Top 5 is not that good of a list:
Nadal - Murray: was good but not out of this world. The ending was very entertaining.
Djokovic - Federer: was a combination of good and really bad but it was mediocre at best.
Isner - Mahut: is just mentioned because of the scoreline but hardly a good match yet alone a great match.
Soderling vs Llodra: The only match that deserves to be in the Top 5. That was high high high quality tennis from both players. Too bad for Llodra though but Soderling definately showed some mental toughness in this match.
Federer - Monfils: Are you guys fricking kidding me? This was a combination of Monfils serving great and Federer good serving and terrible shotmaking from the baseline which earned a fluke win for Monfils.
Here are the real candidates:
Nadal - Davydenko @ Doha: was a very good match. Great comeback from Davydenko and great win.
Blake - Delpotro @ Australian Open: very good match. Too bad for Blake though
Tsonga - Almagro Australian 0pen: 2 players I don't like very much but they put on a very good match surprisingly. Very good ending as well.
Gasquet - Murray: Very good match from Gasquet until he ran out of gas.
Soderling - Federer Rolland Garros: Very good match with both players playing exceptionnally well. Best performance of Soderling that I've ever witnessed (ever better than Rolland Garros 2009 vs Nadal)
Verdasco - Ferrer US Open: That was a very entertaining match. Great ending as well.
My overall favorite match of this year still has to be Nadal Davydenko @ Doha when Davydenko was in god mode from Shanghai 2009 - Doha 2010