Forget about Evra. His contract runs until 2012 with no reason for him or United to let go. Now back to topic...
Even if Eto'o remains with the club next year (hopefully + no reason for him not to) we would still need another striker. With Bojan we have a world class player in the making, but he's still too young and we still need another striker. Why?
Because with the players and style of play we have our interests would be best served with a 4-2-1-1-2 formation. Over the last 4 years, believe it or not, Eto'o has scored against the big guns (except for Real) only when they were a man down. This is explained by the fact that he was marked by 3 players: 2 CB + 1 DM for whom marking Deco would be useless (Deco often tracks back, and is more a threat with his passes).
Another striker alongside Eto'o would allow Eto'o the freedom to track back, escape marking by moving to the wings without leaving the center empty and would give Messi the entire pitch wreak havoc onto. That's why I expect us to go shopping next year for an AM (Hernanes) and a striker.
We should not forget however that we already have Bojan and have expressed interest in Walter da Silva (another 19 years old striker). Benzema would be ideal, but he's been kissing Madrid's Ass this year, is exorbitantly expensive and seems willing to stay for another year. Torres is a distant possibility, and is not cheap either (though with only 2 signings to make, a big splash wouldn't be that extravagant). That's why Villa would be ideal for us: Great striker, no need to adapt to La Liga, consistent, relatively more attainable and at a much cheaper price than the names mentioned above with the added bonus of not being too young or too old so as to come in direct competition with Bojan.
"I think like a genius, I write like a distinguished author, and I speak like a child" Vladimir Nabokov