I know this seems sacreligious, keeping our painted fir floors, but i like them. i am sick of trying to keep a painted floor clean though, and when i repaint this winter, i want to add a top coat sealer.

I'd prefer a water-based polyurethane for ease, but which?
Are the ones used on hardwood floors appropriate for a painted wood surface?
The more coats the better?

thanks in advance,
kbt

We've used Basic's Street Shoe - semi gloss urethane over black paint. That was about 4 years ago, no complaints yet...home owner loves it.