We discussed everything that we'd want in a contract before making the decision to try with our known donor. As it turned out, we all have almost identical "ideals" about how we'd see negotiating the relationships down the road and that was what made us decide to go ahead. He also talked to his parents and we disussed it with ours, which we felt was really important (one potential KD had a mom who was waaaaay to up in our business, and that was a dealbreaker for us even though we liked hm very much).
I posted a thread asking for ideas on what to discuss here:http://www.mothering.com/discussions....php?t=1202511
I got lots of valuable advice and we did discuss almost everything that was suggested in that thread.
I think it's incredible important to have the discussion with your donor before there's a baby, as suggested above. It could be fine but it could also be a case of you two having incredibly different feelings/desires, or having feelings that change after the kid is here.
Also, I'd like to strongly suggest that YOU decide how you want it to look and then approach the donor about how that works for him - I do not think that HE should be the one to decide how this will go, at all. Maybe you suggested that because you feel like he is "doing you a favor" by providing the sperm or something? OK, so think about what you'd be willing to negotiate on, but you should still feel 100% comfortable.