I also strongly recommend using minoxidil 5% once before you go to bed, along with propecia. Keep in mind that it is easier to maintain hair than it is to regrow it.
You could either look back a year from now and wonder if you didn't need the minoxidil, or wish you had used it from the beginning. Think about it.
And if you are maintaining only, then you don't need that much. I suggest putting in on in drops with your hair parted in spacings of 1inch rather than the suggested .5".
Somebody on this site wrote an awesome post on how to apply it. Don't know where it is, but it's in the general discussion forum, written 1-2 months ago.
You won't regret it. Good luck man.