I remember using a package to quickly switch between windows, it was a key like C-something and then on each window a letter appeared for example if you have 4 windows then you have a, b, c and d. Depending on the letter you pressed you moved to its corresponding window. I don't remember the name of the package, I think I've installed it together with some starter kit but don't remember which. Now I use C-x o or S-arrows but I don't like it.