My daughter's father is EXACTLY like yours. My DD is now almost 12, and when she was little, he would come over when the wind blew him over and if I wasn't busy...I felt like you...wanted him to be a part of her life, so since he's so darn unreliable, I took it like that...when he had time, give a call and stop over. I didn't want my DD to have the disappointment of thinking he was coming over, but he was too busy watching Jimi Hendrix videos and fell asleep.
Anyhow...his MOTHER decided that when she moved to Florida, she would put the old "your'e going to send my granddaughter to Florida to see me and like it" routine and pulled Grandparents Rights on me. I was never married to DD's dad and we never had a visitation schedule set up or child support or any of that. And we were getting along REALLY FINE...its amazing how well you can get along with people when you accept them for who/what they are and stop expecting them to be anything else...until evil grandma came along. So, she effectively turned the 'sperm donor' on me, he filed for visitation and I spent THOUSANDS on a lawyer to represent me. Meanwhile, I was working two jobs because 'waste of skin' (as my brother calls him) was on welfare adn his only income was playing in a band on weekends. So, we went through court, got a mandatory visitation schedule set up, where DD would go over to his house...where he smoked pot profusely (the courts said that this didn't matter....he has a RIGHT to see his daughter adn HOW DARE I try to keep them from each other!), never even got her in pajamas for bed, never brushed her hair, and she'd come home with an inch thick coat of plaque on her teeth and in the same clothes I sent her in, with her change of clothes still folded in her suitcase.

Nothing I could do about it whatsoever while I sat at home bawling because I missed her while she was gone, knowing she wasn't being taken care of and not knowing what kind of vermin he was exposing her to. She was five at this time. Oh...and by the way...child support enforcement gave him an order to pay $25 a month in child support...because he's on welfare. THEN, when he didn't pay it, I called CSE and they said there's nothing they could do about it because he's on welfare...can't get blood from a stone or something to that effect.
So, I ended up engaged to my, now, husband and we moved three hours away. Low and behold, 'waste of skin' hasn't seen her since June of 2000 because he doesn't have a car to come get her. So, all seemed well and good with the world until I have a Court Marshall at my door with court papers from the evil grandmother in Florida (Evil Empress of the Negaverse, as DD calls her) suing me for Grandparents Rights. To make a long story short, when I moved here, I became unemployed because I became a stay-at-home mom. BUT, I wasn't married to my husband yet, so now I was the single mom out of work. I got a court appointed attorney and Evil Empress of the Negaverse had to come up here (after I filed for a change of venue from where I moved from) and sit in TRIAL for a DAY AND A HALF

...and she LOST!! So, after all her terror and stirring up of sh*t in my life, she got a nice, hefty bill from a lawyer and still didn't get her way.

Sad thing is that I would LOVE to have her see my DD way deep down inside, but I know the amount of crap she'd bring to my life just wouldn't be worth it.
In the end....nothing is better than telling a dead beat dad to just half off and get the heck out of your daughter's life. YOU don't need the aggrevation of trying to get him to get off the stick and be a real dad, because it's jsut not gonna happen. Interested dads (and moms) are interested from the git go, naturally. You'll only be setting yourself and your daughter up for dissapointment. If you go for child support, you'll only remind him every month that he should get something in return for his money and bug you and cause strife in your life. I say, but this is my opinion, just cut him off...don't ask for child support (especially if he's not worth much anyway) and raise her on your own. You'll be much happier in the end.
Then...if he comes around and wants to genuinely see her...rethink it. But I honestly think you're beating a dead horse in allowing him to cause chaos in your's and your daughter's lives. It sounds as if you aren't in an active court case with him, so I wouldn't start one. Just sit back and let him do the suing...and then YOU can get the court appointed attorney, if they have that where you live. Court appointed attornies are MUCH more willing to go the distance with you. If you are forced to hire one to represent you, then they try talking you out of things like trial because they worry they won't get paid for it...if the state pays for it, they know they'll get paid...get my drift?

And your daughter's well-being is worth it.
Really, mine and my daughter's lives are so much better off since we cut out the screwed-up paternals. Trust me when I tell you that I never, ever thought I would cut them out when I was pregnant and when she was a baby. But one can only take so much abuse and you realize that people are only out to hurt and control and that's not cool for ANYONE. My daughter's 'sperm donor' (you know, he actually got mad at me on Father's Day once...he acutally said, "You know, I AM her FATHER...you could have gotten me a card, at least..." and I said, "When they have Sperm Donor day, I'll be first in line to get you a card, at least"...jerk) wasn't the least bit interested in seeing her or being a beneficial father to her...he was only acting on guilt and on his mother's orders. Terrible. My daughter is almost 12 now and hasn't seen him in about 6 years. And we are all SOOOO much better off for it. No child support, no visitation for a truly dead beat dad. In the event, when she gets older, she wants to see him, I'll help her, but only on HER terms, not HIS or his horrible MOTHER's.
Good luck to you...I've been in your shoes before and I know exactly your frustration.

It will get better, trust me.