I have tried a couple of different versions (Mepis and Suse) of Linux, I installed Ubuntu about 6 weeks ago after having problems getting other 'flavours' to recognise and configure my video card correctly (Nvidia FX 5200).
There is a lot of software available for Linux but not the large variety that is available for Windoze.
Linux is a *very* different operating system to windows and is much easier to break, that said it is much more powerful. Configuration of a Linux system is more complicated than windows, it is a lot more command line orientated and the transistion from Windoze to Linux means you will have to learn a lot!! (and I do mean a *lot*).
Probably the most stable and supported (and oldest) is Debian Linux.
Here is a link to a web site that has 325 different 'flavours' of Linux
http://www.gridter.com/linx/linux.html This is a link to a lot of useful Linux documents/ reference cards
http://btp2x1.phy.uni-bayreuth.de/ar...uals/refcards/ Here there is a "how to" on security under Linux
http://tldp.org/HOWTO/Security-Quickstart-HOWTO/ And a link to the version I am running
http://ubuntuguide.org/wiki/Ubuntu_Edgy Many programs under Linux are 'Opensource' or free ware (the best description I can find of opensource) if you want to play games then many are commercially available.
Problems I have encountered:-
Some web based videos do not play
Firefox will suddenly decide to quit for no apparent reason (most noticably in the chat room on the forum)
Even when you follow the instructions on how to install a particular program it does not install.
Certain 'flavours" do not have the support available that the new user needs.
Certain IRC support channels although they specify they are newbie friendly are not. (on one occaision because I asked a question that the moderators thought was easy to answer I actually got kicked from the channel)
My personal reccomendation : -
If you want to make the move to Linux do your research, make sure ALL of your hardware are compatible and supported by the 'flavour' (Distro in Linux speak) is supported.
Go onto the support chaneel for the Distro you have selected before you install and ask as many questions as you can think of.
If possible get a second hard drive and install onto that using your computer BIOS settings to select which drive to boot from, before you go the whole hog and install a boot manager and dual boot system (which I do not personally recommend at all, one experience I had during my testing phase was a failure of the boot manager in such a fashion that I had to reformat the drive).
I hope this is some help to you.