Where's the Line?

My last post was about the sermon given on Sunday and I have another part of it I want to digest. The teacher on Sunday was talking about deeper devotions with God and during our young marrieds group when we were discussing the notes for the sermon beforehand, we got to talking about devotions as in "quiet time." I'll be the first to admit that I'm the worst at keeping a regular quiet time where I sit down, pray, read my Bible, write in my journal, and/or read part of a Christian book (I'm trying to get through Utmost for His Highest). Even when I'm sitting at home looking for a job, I can't seem to find the time to have a quite time!
My biggest struggle is that I have conflicting feelings about wanting to spend quality time with God without it becoming legalistic. I've heard that we should think of our time with God as a time with our friends-- well, I don't see my friends that often. I see some of them once a year! Those who I'm closer to, I'll see every couple of weeks or so... is that how often we should spend time with God? I don't think so, but where is the line-- The line between having to do it because we should and wanting to do it because He's God? Do I just have to think about it as something I have to do and it will become something I want to do? But should God be like a habit? That just seems weird! Is praying in the car on the way to wherever enough? Is sitting quietly without any sort of religious text around okay/enough? Or is it just an "easy way out" by putting the least amount of effort into it while wanting the most effort put in on the other end? I can tell you that friendships/relationships do not last long if that's what someone does! Relationships require equal input and output-- I can't expect God to be any different.
But it all goes back to my initial question-- where's the line? Can a overwhelming desire to read my Bible and take time out of my day to spend time alone with God just be created out of thin air? Does it take some initial habitual reading to get into it? It'll take some more digesting and prayer and whatever to strengthen my relationship with God. Anyone got any other thoughts on this subject?