I'd recommend Ubuntu Server with the LAMP installation option. You can install a GUI or keep it command line only. Being new to linux a GUI would probably help you as well as the easy to use style of Ubuntu. I'd recommend Ubuntu 12.04 which will be there new LTS version and officially released as stable on the 26th of April, however i'm using it right now and it's amazingly stable currently and wouldn't worry about it not being stable. It will automatically install any drivers for your system and give you a smooth new ride into the Linux world.
Some reasons to move to Linux:
Security is higher then Windows
Chance you'll get a virus are slim.
Linux runs on 90% of the world's super computers for a reason, it's fast and flexible while staying secure.
Besides saving money on the OS, Linux has a long list of open source applications that run smoothe and better in some cases then any windows application.
Linux is the ideal OS for the a web server for these reasons. With a web server, nothing is more important then speed and security, and that's what Linux has to offer you.
The Ubuntu Software Center offers a long range of free, amazing software that you can look through for a long list of IDEs and anything else you could want.
Try your first cup of ubuntu with your web server and let me know how it goes =)
P.S. once you have it installed, to install the GUI just type this in the command line:
sudo apt-get install Ubuntu-Desktop
Once installed, launch it by this
Then it will default to the gui every time after you first launch it. Pretty easy, the reason I recommended the server version is it is more sudo demanding which makes it safer then the desktop version, but both are safe and would do a great job.