Among the different aspects of game development, I think I’m weakest at sound matters. This is something that has to change though, with the success that audio-based games have been having, such as the IGF winner Audiosurf and the Python-based Frets on Fire.
It’s good that Kunal Joshi pointed out in the comments the amazing DrPetter’s sfxr, an excellent (and free!) piece of software that generates retro-style sound effects. This was used by Kian in his very funny, and VERY ORIGINAL (you have to see it!) game You Have To Burn The Rope.