Klaas-Jan Huntelaar!
EDIT -
fuckcocktercock has asked me to edit the post, so here's why I want The Haunter in United.
Two years ago, when The Haunter was a n00b, I started a petition to bring him to OT. It was when Ruud left. But, the "ultras" wanted someone who can run at 100mph, while doing step-overs, 1-2s, making triangles and doing jumping jacks, to suit "our style", whatever that is. I was booed out of the 'hood. But I never gave up.
"We also have Saha!" 
Then, last season, The Haunter proved his worth once again. 9 goals in 9 matches in Europe, 1000s of goals in the Dutch League and what not. Then came the Kezman comparison. Regardless, we bought Tevez, and all worked out well. But during this season as well, The Haunter smashed them in like there's no tomorrow. Now, he's got Madrid, Juventus and Barcelona up his ass for his signature, he has got a place in the National team, got selected for the EURO 2008, and now, everyone is getting to know what I meant back then. Now I'm not saying I'm Wenger, far from it, I'm way better than him, I'm just saying I was right then, and I am right now when I say The Haunter is the final piece in the jigsaw. We NEED a finisher. Rooney has misses to many chances that it's not even funny. He is not a finisher.
KJH is the perfect striker to play upfront when we want a lone striker. He can hold the ball well, he can pass well, comes from the great Dutch academy. I don't know why people think KJH is not "fast", or quick. He is quick enough, faster than Berbatov at least. Not to mention, we don't have ANY arial threat with us apart from Ronaldo during open play. I can go ahead and safely say that KJH is the BEST header of the ball in the world right now.
The problem with Berbatovs and Benzemas is the drama queen element. they'll bring their own baggage. Benzema had a fight with Ben-Arfa, leading to a fight between Ben-Arfa and the manager, and Berbatov is as sulky as he is silky. I think out of 60 odd games, we can give KJH 30 games, 15 from Rooney and 15 from Tevez, not to mention the subs appearances, around 40 appearances in his first season for Manchester United, I don't think he will complain.
Santa is Saha II. The fact that he didn't get injured this year should be deemed as a miracle.
I don't even know why someone would want a washed-up has-been-before-he-even-was-a-has like Ashton! What next, Adebayor?
Luis Fabiano, I can't say about him as I haven't watched any of Sevilla games.
But I doubt it (KJH to United) will happen though. He'll go to Madrid, they're the double defending champions
as well, not to mention as big a club as us, if not better. Then they have Ruud, Robben, Sneijder and that retarded left-back from Holland-U21s, Drenthe.
The only thing that might shift him towards us is the fact that Madrid already have 8 strikers, so unless they offload 5, I don' think any striker would like to go there. Plus they're after Villa as well.