Best player ever.
In my mind, there are 4 primary ways a player can contribute to the team: goalscoring, assisting, helping keep possession, and tracking back/defending. No one has ever come close to Messi's combination of those things.
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Goalscoring: Goes without saying. 86 goals in 2012 so far. 73 goals for Barcelona last season. His ability to create goals out of thin air is extraordinary, but what really sets him apart nowadays is his inhuman accuracy. Between this season so far, and last season, Messi has 73 league goals in 281 shots. He scores 26% of the time he shoots! For context, Cristiano Ronaldo has scored 15.8% of his league shots during that period. Falcao has scored 22.7% of his shots. Benzema has made 19% of his shots. Van Persie has made 17.9%. Rooney has made 16.8%. Aguero has made 17.4%. The only major player with similar accuracy is Mario Gomez, who also scores 26% of his attempts. Of course, he's a real pure striker, so he is only taking high percentage shots in a way that Messi is not. Gomez would never be able to keep up his scoring % if he started attempting a lot more non-poached goals. And that's the point that is truly extraordinary. You can only poach so many easy goals; if you're taking more shots than anyone, the difficulty of those shots is inevitably higher on average. Yet, Messi takes more shots than virtually anyone AND is still the most accurate.
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Assisting: He has been the best in the world at this for a while. 28 assists last season, 22 the year before that. I believe he led the world in assists both seasons. The extraordinary part of it all is not so much the assist numbers (which are absolutely ludicrous considering he basically never has those numbers padded with free kick/corner assists; it's virtually all from open play). The absurd thing is the shear dominance he has over through ball stats. He is attempting them less this season (probably because there is literally NO other in-form Barcelona goalscorer to aim at), but last season, he led La Liga with 1.5 accurate through balls per match. Cesc was in 2nd place with only 0.7! If you look at # of accurate through balls total, it looks even more absurd. He passed 56 accurate through balls last season in La Liga. Joan Verdu was in 2nd place with only 21! The numbers are similar for Champions League too last year. He passed 1.3 accurate through balls a match in the CL. Cesc was in 2nd place with 1.1, Kroos was in 3rd with 0.8. He also lead La Liga and the CL in accurate through balls in 2010-2011 as well. So far this season, his numbers are near the top of the leagues, not at the top, but I still think it's clear he has the best final ball in the world given the last few seasons.
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Helping keep possession: I think this is something people know Messi does, but don't quite understand the uniqueness of. Last season, Messi made 63.8 passes per match, which was 9th place in La Liga. Only 3 non-Barca players were ahead of him. This is just an ASTRONOMICAL amount of passes for a forward. The closest forward to him was Iker Muniain with 40.9 passes a match or Ronaldo with 37 a match if you don't consider Muniain a forward. Both have lower pass completion percentages than him. He was 35th in La Liga in pass completion %, despite being a forward who is constantly making dangerous passes in traffic. Only Higuian and Callejon were forwards with higher completion %, but they had very small sample sizes (less than 20 passes a match for each). In 2010-2011, Messi made 67.7 passes per match. This was 6th place in La Liga, with only 1 non-Barca player ahead of him. The closest forward to him was Juan Mata with 44. He was also 21st in La Liga in pass completion %. Pedro was the only forward with a higher completion percentage than him. This season he has 57.7 passes a match, which is 10th in La Liga, with only 3 non-Barca players ahead of him. All 3 of those players have a lower pass completion % than him. Pedro is the closest forward to him, with 40.6 passes a match.
People might say that he is only involved this much because he plays for Barca, and that's partially true but two things need to be pointed out. First, the other Barca forwards are never involved as much as Messi. Pedro has significantly fewer passes a match than Messi, even taking into account that he is more often a sub. Same with Villa. For instance, in 2010-2011, when Messi and Villa both started virtually every match (so one player being a sub a lot didn't mess with the per-match numbers), Messi made 67.7 passes a match in La Liga, while Villa made only 23.7. Messi is unique even among Barca forwards. Second, part of the reason Barcelona is such a passing machine is because of Messi. They wouldn't be able to keep possession nearly as well if Messi (and the other forwards for that matter) just kept up top waiting for a through ball. You can't just discount his possession contributions by saying they are accounted for by something he helped create!
Anyways, the numbers get EVEN MORE stark when you look at the CL. In some easier La Liga games, Messi rests himself and doesn't get as involved because he knows that, against weaker teams, Barca's midfield can dominate possession without him and he will be just as effective exerting less effort in a more forward role. This is less true of the CL, where even Barca's midfield can need help. As such, he contributes even more. Last season, Messi passed 80.9 times a match at 87% accuracy. The year before, it was 68.8 passes at 89% accuracy. This year, so far, it's 69.5 passes at 85% accuracy. Let's look at last season more in depth. He had the 6th most passes per match in the CL. The only non-Barca players ahead of him were on teams that crashed out in the group stages (i.e. there was was a low sample size for their numbers). The only Barca players ahead of him were Busquets and Alves by a little, and Xavi, obviously. It bears pointing out that Xabi Alonso had fewer passes per match in the CL last year than Messi.
These are truly astronomical numbers. 60-70 passes a match in the league and 65-80 passes a match in the CL are the numbers of dominant CMs. For instance, Cazorla is probably the best midfielder in the PL this season, and he has 68 passes a match. Somehow, the same player who just set the record for most goals in a calendar year ALSO has those kinds of passing numbers. It's mind-boggling.
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Tracking Back/Defense: I don't have much to say about this statistically. Messi can be lazy at times because he is conserving energy, but he does track back more than the average striker I think.
