Who was Arsenal's greatest signing this summer?

Arsene Wenger didn't splash out much cash during the summer transfer window (summary of Arsenal's transfer window activity here), bringing in only Bacary Sagna, Eduardo da Silva, Lassana Diarra, Lukasz Fabianksi, and Havard Nordtveit. However, there is no question that we have gotten some quality players through Wenger's astute eye for talent.

Some would argue that Wenger himself was Arsenal's greatest signing this season. Seeing him finally sign after months of speculation over his Arsenal future was a great relief to Arsenal fans. Having our manager stay on for another 3 years (without a get-out clause) was probably Arsenal's greatest coup this summer, but are some of Wenger's signings even more valuable than himself?

Bacary Sagna has been a rock at right-back since he came in from Auxerre for a fee rumored to be around £6.1 million. His defending has been more solid than any since Lauren was on top of his game, and his overlapping runs have provided excellent support up front. He's no Gael Clichy in terms of his dribbling skills, but his tough tackling adds a needed sting to Arsenal's back line.

Arsenal fans will be hoping that Eduardo will be able to provide the same sting up front. Dudu's arrival was controversial amongst Arsenal fans, with many looking for a more established striker after the loss of Thierry Henry and others happy to have signed a striker who could really put the ball away. I wasn't too keen on him in the beginning, but after seeing him play I began to believe that he could become a goalscoring left-winger in the mold of Robert Pires. Only time will tell, but Arsene may have once again unearthed an undiscovered talent in Eduardo.

The final major signing of the summer came in the form of the unwanted Chelsea utility player Lassana Diarra who came to Arsenal in a surprise final-day transfer. The 22 year-old has bundles of potential that he was never allowed to show with Chelsea and will be great support as a defensive midfielder when Gilberto is out. The 'new Makélélé' has yet to debut for Arsenal, but I think that there is little doubt that he will have some impact this season.

Arsene Wenger has once again managed to buy a fair amount of talent with a small amount of money, and it will be interesting to see which of our new signings has the most impact over our next few seasons.

Who do you think was our best summer signing?