D90 up.
I think if he wants to AF on a 50 1.8 then yes, D90 is perfect
Not exactly ----- D70, D80 does!
What is the alternative if he really wanted the D3000? Is there a lens close to the 50mm that has a built in AF motor that would do the same job? Portraits?
Are there limitations of available lenses for the D3000?
Which Nikon DSLRs have the AF motor built into the body? I ask as a mate is thinking of buying the D3000 and wants to buy a 50mm too but i am sure that is one of the Nikon range that doesn't have a built in AF motor?
Please have a look at here for the lens compatibility with reference to the body you (are going to) choose.
I'd get a D3000 for the wider lens choice (the point above re the 50m 1.8 notwithstanding)!