OS independent is the web app. I prefer the traditional PHP/MySQL but YMMV. Then again it depends on what you are developing. PHP is good for what I'm doing

OS independent is the web app. I prefer the traditional PHP/MySQL but YMMV. Then again it depends on what you are developing. PHP is good for what I'm doing but not necessarily for games and such. If I needed to make something that ran ON the user's hardware Python or C would be my choices.