I absolutely love Marty too (and have recently added him as a character in the RPG thread). I have missed him so much since he hasn't been on all season (which I understand... If Rory's not at Yale there's not much opportunity to work in Marty). I truly hope that with Rory's return to Yale we will see more of Marty. It's uplifting to hear that ASP would like to work him in, schedules permitting.
I personally see Marty as Rory's Luke. He's stable, kind, smart (he did get into Yale), funny, unselfish in his friendship with Rory, giving, caring, sensitive, reliable, patient, loyal, trustworthy, humble/not egotistical, helpful... I could draw parallels forever

. He's the one who belongs with Rory longterm.
I too loved the scene where Rory fell asleep in Marty's room. I could be too overanalytical, but I think that scene has an important hidden message in it. For a girl to fall asleep in a guy's room, she must have felt safe. While I'm sure she didn't consciously think "I trust Marty, so it's safe for me to fall asleep," that's the message that her falling asleep sends. It just shows a deep level of trust and security in the friendship. Think about how much Rory trusts Logan. On several occasions she's passively suggested that Logan was flirting with other girls when they were officially going out. While she enjoyed the fun side of his playboy personality, she doesn't trust him because of the playboy personality.
About Marty being Rory's boyfriend, I have some torn feelings.
1) I worry that realistically the writers won't make them a couple because he isn't exciting. I think we have to admit that GG writing has been leaning more towards the sensationalism/soapopera crap to gain more viewers. Jess and Logan were exciting and stirred up a lot of drama. I don't see Marty has fitting into that category, so he might get overlooked by the writers.
2) I don't think I want to see Rory take Marty as her boyfriend... YET. I think Rory is still incredibly immature in relationships and has a long way to go befor she deserves Marty (yes I said it... <ducks from tomatoes>). Plus I wouldn't want them to throw Rory and Marty together before they bring closure to the Logan break up. It would really suck if Logan showed up and goes "I didn't think we broke up, that was just a misunderstanding on Honor's part" and Rory goes "Oh, oops. Bye Marty."
3) I don't want the writers to play the Ross and Rachel game where once Rory sees how great Marty is, he is with someone else or claims not to be interested in Rory, and so on back and forth. It's been done, writers.
4) What I really want is Rory to finish straightening up, realize that what she's looking for in a guy isn't just a fun good time, but a real mature, caring, nurturing sort of relationship, which I believe Marty can provide.