I have to say gouache is a delight to work with. It is basically opaque watercolor and is a very versatile medium that is under-appreciated. It can be thinned and used like watercolor or used opaquely with a similar look as oil paints (except it is matte and cannot be used too thickly due to risk of cracking). It is one of the preferred mediums for illustration due to its extremely fast drying times and matte finish which allows for easy reproduction.
I had this 10 tube gouache set from Daler Rowney which I bought about 7 years ago but never used. I got motivated to try it a few months ago after seeing some awesome work on the artist website wetcanvas.com. You can see some of my gouache work in the Gallery section.
Below is my latest gouache painting. It is based on my own picture which I took when I toured the coast of California with family back in 2007. I'm falling in love with seascapes and this one was so much fun to do. Even though I signed it, I still consider it a work in progress (WIP). I'll have to look at it for a few days before I call it done and move it to the Gallery.