I converted from Windows to Ubuntu bout 4 years ago and haven't looked back. The Unity UI in my mind is just as visually appealing to a consumer as OSX's (which might be a slightly controversial opinion!)

In terms of IDE, I think it really depends on what you are using it for. I've been using Cloud9, a web-based IDE, quite extensively recently for Javascript work but you still have your standard Eclipse and NetBeans, which are both fairly extensible. You might also consider taking a jump into Vim.

The great thing about Ubuntu is the ability to create a USB Live Distro. Road test it before committing if you are worried. But I don't think you'll be looking back :)