For spaghetti dishes as well as dishes normally prepared with angel hair pasta - I prefer thin spaghetti, it's the best of both worlds. I find regular spaghetti a little to heavy, and angel hair is a pain in the but to cook and eat sometimes because it all sticks together.
I love mini rigatoni for all other dishes. Although I recently discovered a brand of elbow pasta that actually has ridges on it as well, which was really nice because it works well with stuff like ghoulash too.
Some of my least favorite are bow tie pasta - too dense and heavy and kind of looks sloppy in dishes. I also don't care for cavatappi either, way too heavy and chewy - the pasta overpowers the dish and it takes too long to cook.