Two, with the promise of a third.
An Omega B-600 came with my D3. Decided I wanted to be able to print 16x20, want and actually doing not being the same thing, so I sold the B-600 and picked up a Pro Lab D6. Some time in the next week, I'll be rescuing a D5XL with a color head
To recap, I have an Omega D3, because I think the autofocus feature is a neat trick, though having to change the condensers and cones around is a bit of a pain. I got the D6, to print larger, the zoom condenser makes switching format easier and no need for cones. And the D5 is just to have a color head. I don't shoot color. Other than the fact that all of this has cost me little, it's amazing my wife hasn't murdered me yet. Then again, she'd have to explain all of the enlargers and the dead body, so maybe not.
The only other thing I may ever need is an 8x10 enlarger, if and when I ever buy a camera. At that point, I'd probably sell two of the above three, if not all of them.