I've done a fair bit on walls, but having seen that lovely stamping spread in Martha Stewarts magazine that went from a headboard, to wall and lamp...I've been thinking about starting at a ceiling point in the bathroom with cascades down to a mirror and towel rack.
All that being said, I've used only acrylic paint. It's easy to work with and can easily be wiped away if the stamp slips while working. I keep several artist brushes on my plate of paint so I can fill in were necessary. I use one of those little sponge/throw away brushes to apply the paint to the stamp. If the stamp starts to looks "messy with paint", it is good to take time to clean it. Although you can get a fair bit of stamping done before that point.
I also use the artist brushes to streak other colors of paint onto the stamp for a more varied look in color (When I stamp pinecones I use 3 shades of brown).
Have fun with your project!
Annette
http://stamponthis.com