With my first draft in the vault for awhile, I've found that starting up on other stuff is much, much easier.
Before I got into a routine, it was tough getting myself to write. I've long said that the most important part of writing is actually getting your can in front of the computer and just typing. Now that I'm used to it, things are much, much easier.
I've come up with a couple more ideas I think are good, but I'm trying to organize them now. I don't want to start any of them until National Novel Writing Month starts, but I should be good and organized for my first foray into NaNoWriMo.
In the meantime, I've been enjoying doing some other stuff - short stories for the most part. The one thing I've noticed is that things come much easier to me know. I don't have the novel hanging over my head any more, and I was worried about this limbo between NaNoWriMo, but I can tell that my writing is better. Even with this short stuff.
Top benefit of finished first draft: I'm a more confident writer, and that has led to better writing.