There are many types of operating systems for Linux, called Linux distributions. There are currently over 600 distributions (or distros) today. Some are very light, while others allow you to run Linux with your other operating system.
There are also full fledged systems that come complete with applications. What you choose depends on your needs and what your intentions are.
For Those Who are Just Curious
If you just want to give Linux a try, use Live CD distributions like Knoppix. Linux will boot straight from the CD. You can run Linux without installing it on your PC.
The Live CD also lets you run Linux programs, create and save files in the hard disk. You can also use Wubi to install Ubuntu (a popular Linux system) in a Windows based PC. Wubi will install Ubuntu like any ordinary app.
For Those Who Have Never Tried Linux
Mint is one of the easiest to use. Linux Mint is also supported by numerous programs. Linux Mint comes with a tool called mint4win that lets you install the OS without affecting your Windows configuration.
Ubuntu is another good choice for beginners, as well as Fedora (Red Hat) and OpenSUSE (Novell). Like Ubuntu, these two Linux distributions are friendly towards new users. Xandros is a commercial distro, but lets you run popular apps like Microsoft Office, Photoshop and other Windows apps.
Linux for Old Computers
The Puppy Linux Live CD can run on computers with only 64 MB of RAM. The CD can boot from a CD drive, zip drives and USB flash drives. Xubuntu also uses few resources, as does AntiX. AntiX can run on computers with Pentium II specs. Other options for those with old computers are Zenwalk and Damn Small Linux.
Linux for Work
Xandros is another good choice. Ubuntu can also be used in severs. Red Hat is favored by many though, due to its tight security features.
Linux for Netbook Users
The top choices are Moblin, Jolicloud and Ubuntu Netbook. If you have Ubuntu in your desktop, you can use it to install the OS to your Netbook. Follow the onscreen prompts for installing the appropriate packages.
For Power Users
Arch Linux is the choice of many experienced users. The distro allows you to make a Linux installation from scratch. This system does not have a GUI, so it is for advanced users only.
The vast array of Linux distributions ensures there is a system for users regardless of their experience. From the user friendly Ubuntu to the server oriented Red Hat to the advanced Arch, there is no shortage of options for anyone interested in trying Linux.