One thing he's said in an interview is that he wants to go to a team that maybe aren't world class, and help build them up to that level.
To be honest I don't think that Beckham and Donovan would make that good a pair.
From what I know of Donovan, which is what was said during the WC, is that he's fast, and deadly?
Beckham is old. He's slow. He seems to prefer going up the right wing at his own pace, and then crossing the ball into the area. He's also a player who, when motivated, can take advantage of set pieces and completely devastate a defence - as has been demonstrated countless times with his curving free kicks and corners. Sadly he's been getting a lot fewer on target these days. He only got two during the WC.
How exactly does Donovan play? I'm just guessing here. The two might compliment each other tremendously, and I just don't know it.