I'll second the water-based poly recommendation. I recently bought two pieces or solid wood unfinished furniture -- an armoire and a computer desk. Because it was more involved, I had the store finish the computer desk (they used oil-based poly), but I did the armoire myself with a satin water-based poly (WBP).
The WBP was very easy to work with. It goes on with a milky look, which helps you get even coverage and the brush marks (in my case I used a sponge applicator) disappear almost instantly. The one thing you have to be careful of, though, is drips, as it can run easily.
