There are many choices of operating systems that can be downloaded for free. Here are my observations on those which I've used most.

Fedora is one of my favorites. The fedora project is a collaborative effort of Redhat and the open source community. You have to be a bit of a geek to use fedora because: 1) there is a new release every six months 2) it is 'bleeding edge' - sometimes you get hurt by the sharp edges. For the less adventurous redhat offers CentOS which is more stable.

Debian is another distro of linux that I use regularly. I started using it because I had a system that did not have a CD drive and at the time Debian was the only thing I could find that would allow me to install with just a floppy disk. I made a bootable floppy and finished the install over the internet. I've kept Debian on that system and it works fine. You don't have to be as much of a geek to use Debian, the releases are less frequent and when there is a new release it has been well tested and is ready to go. With Debian you do not get the latest greatest versions of all the apps, but everything pretty much works 'out of the box.'

Solaris is a great vehicle for someone who wants to learn about this version of unix which has widespread commercial use. It is strong on security and for someone who has an interest in becoming a unix system administrator or a java programmer downloading and installing solaris is a wonderful way to learn new skills. Since Sun created the java programming language they know more about it than anyone else and they offer many resources to learn about solaris and java.

Ubuntu is an extremely popular linux distro. I have not used it much, but when I did use it I found that it was very easy to install. Unbuntu has been at the top of the list on the linux top ten site (meaning it has been downloaded more than all the others) for several years. Among the reasons for this are the ease of installation and the wide variety of applications that are included in the distribution. The main reason I did not stick with unbuntu is that they use python for things that most other distros use perl for and I am a perl programmer. Since they avoid using perl I have avoided using unbuntu. Nonetheless, it seems like unbuntu would be a good choice for someone who is looking for a free operating system that doesn't take a hard core geek to get up and running.

FreeBSD is a distro with a reputation for being very secure, and very stable. I do not have much experience with this, but those who like it like it very much.