There are some interesting new papers that aren't really paper at all, but are plastic, instead. This means watercolors don't soak into the paper. Colors are more vibrant, and they run more freely on a wet surface. Also, since the pigment isn't absorbed into the paper, it wipes completely away. This means "mistakes" can be totally erased, but it also means that if you rework a section, you will lift off the paint you've already put down. Here is my first painting on this kind of paper.
And here are some closeups of sections that I particularly like: