What is the best of the rest (OS) I have read about in this forum?
The right tool for the right job. As you are familiar with different 'windows' operating systems, there are many different 'linux-based' operating systems. We typically do not describe the windows version by the kernel (we call winXP 'XP' and not NT 5.1, ect). This being said, Linux-based operating systems have a lot in common, just as NT-based operating systems (2000pro, XP) have a lot in common.
There are differences, though. This is where the 'right tool for the right job' comes in. What are you going to be doing with your computer? Assuming you want a normal desktop operating system, then do you want a 'techie' linux OS or a Linux OS that is more integrated? Do you want to concentrate on learning more about your computer, or just want everything to work without worrying?
These are individual questions; and I can no answer them for you. My answers lead me to trying RedHat/Fedora Core, Slackware, and Suse. I like Redhat the most, and that is why I use Fedora Core III right now. I tried slackware, and it has its benefits, but wasn't right for me. Suse was wonderful, but there is just something about it... I think it was Yast that i didn't like.
Try Ubuntu and Knoppix Live cds to get a feel for if you want a gnome-based install or a KDE-based install
Novell Desktop Linux 10/Suse 9.3 will be out this month, and Fedora Core 4 will be out to mirrors within a few months.
What are the main differences, compared to what I have now (XP Pro, et al)?
Linux-based operating systems have a different directory heiarchy. There will be no C:\Program Files... don't expect it. There will be no 'C' drive, no 'D' drive, ect. Everything is built from the root directory, or '/'
Your home directory would be /home/username/. Most programs are install in the /usr/ directory. Most system-wide configuration tools are in /etc, while most user-prefference configuration would be in directories in your /home/username/ directory. /dev is a list of all system devices. Extra hard drives and partitions need to be 'mounted' to a spot on the filesystem heiarchy. you could choose '/mnt/win/' for your windows directory, or just make '/c' like i used to.
The software will be different. As you do not run windows software natively on a mac, you do not run windows software natively on linux. You can, however, use ports. Firefox exists on both platforms, for instance. Most software can be easily upgraded, which is of benefit to you since it is not so in windows. Typicically i use apt-get (graphical program is Synaptic) to update and otherwise install software. Fedora Core comes with 'yum' which is similar, with another graphical 'up2date' program. Suse/Novell has Yast.
there are many differences... feel free to ask
edit: missed a question
I have a 60G and a 40G hard drive. The 40G is split into 2 20-gig partitions. What is the best way to get ahold of the OS you recommend, and how much does it cost?
Your hard drives will be hda and hdb (assuming they are standard IDE hard drives)
There will be a number after the hda or hdb. If your 60gb hard drive is hda, and you only have one partition on it, then it will only be hda1. Your 40gb hard drive has two partitions on it, so most likely you will have hdb1 and hdb3.
All of the OS's i recommended above are free (and Free). You can download their ISO images and burn the install cds yourself, or you can buy the media.
