Freelancers Holy Triangle, pick 2

You know the saying we freelancers tell our can have it good, fast or cheap, pick two. Well, after 12 years of being in business, I've come to a similar conclusion regarding the clients I take on.

My client should be:
1. Pleasant to work with
2. High paying (i.e. not tightwads)
3. My chosen niche (favorite subject matter)

I demand at least two.

Currently, I'm working with a pair of highly detailed, slightly scattered and somewhat demanding clients. Normally, we would call them PIAs. But because I LOVE the project and they aren't questioning my prices, I can easily deal with their idiosyncrasies.

I've learned that to accept less than two of the above qualities inevitably leads to frustration. I've decided life isn't worth it, no matter how much I want to fill my pipeline.

What do you think? How do you define your ideal client? What parameters do you put up for accepting clients?