There are several flavors to look at. I am still kinda new to the Linux gig, but here's my take.
Linux distributions can roughly be divided into 2 groups....based on how they package their software. Debian flavors have an apt system, Systems such as Red Hat use RPMs. I prefer Debian Based systems.
The following is an overview of what I believe constitutes great distros for desktop environments. There are different distributions based on developer's needs or concepts. Live CDs will run off of your CD ROM, without touching your hard drive. Using these types of CDs will be the best way of seeing if your major computer components will be detected.
Examples of full live CDs are Mephis, Knoppix (and Gnoppix), Ubuntu and others.
There are micro live CDs that fit on a thumb drive or business card CDs. These lightweights are 50 MB to 200 MB and are reasonable to download off of a dialup. Examples are Feather and DSL.
Next comes install Distros. Ubuntu offers an install CD as well. Additionally, there is Debian itself. You can download a netinst CD from Debian. That will be a ~120 MB Download. That includes all of the core operating system components and will allow you to configure your computer for your needs then download the rest of what it needs. You must have a broadband connection for any of these.
For Servers, I suggest CentOS. It is based off of Red Hat Enterprise, which is a stable, commercial distribution that is suited for production servers.
Linux plays well with Windows. Any distro you pick will install Lilo or Frub wich are boot loaders. At boot time you have the ability to load Linux or pass the control to a secondary boot loaders (Chain load into Windows). Sounds complicated, but all you have to do is arrow up or down to your choice.
Each distribution may choose a main Window Manager, Gnome or KDE. Find out which one you like.
<- You can research all of the top distributions and download yor preference yourself.
*********** Special note: You must have a swap partition that is double the amount of RAM for your computer, and have a / or root partition. *********************************
I suggest at the minimum also including a /home partition to keep your personal information separate from your system...just a good policy.
Thats all I have for now. Let me know if I was able to help!
If you have any more questions, post em and we'll take care of ya!