Yes, HeatSink, I see your point. But, I guess, because the applications that are listed are Debian based, it wouldn't do MS or Mac users any good. But a clearer message as to why could be better.
Well, no1important, that's a real can of worms there and open to personal bias and opinion.
Q: Why so many versions?
There are so many different versions (or "distros") because there are so many different ways to use and utilize the Linux OS. Many are geared towards the novice desktop users, while others are more for the "techie" type people. Some are built for specific hardware requirements, while others use certain file management systems. Some are built for automation of functions, some are designed to give the user complete control.
All are good, all are useful, and all meet different needs of their users.
Q: Which one is easiest?
This all depends on the individual's skills, desire to learn, and tolerance levels. I think a good place for a beginner to start is with one of the "live" distros. Kanotix, Mepis, Knoppix, Ubuntu, Morphix, and Mandrake Move are all good places to start.
What's nice about a "live" distro is that it runs completely from the CD and does not require you to do anything to your existing OS to run. Simply insert the CD and re-boot your PC. Eject the CD and re-boot again and you're back to your old OS.
Kanotix, Mepis and Morphix have easy install features that lets you install the Linux system from the CD onto your hard drive.
For non-live distros (in other words, right to hard drive), some good beginner distros include Mandrake, Yoper, ALT Linux, Fedora, and Libranet. These are distros that I've tried myself and consider to be easy enough for the average or novice PC user.
My personal preference: Kanotix. It's now running on two of the three PCs I have in my home. The third is running Morphix-light, being an old PI and all.
Q: Should I dual-boot?
I've only dual booted with W98 and have not tried to do this with XP. The concept is similar, but I cannot say if it is truly fool-proof. From the information I've read, it's highly recommended to back up all XP data before attempting (which is good advice no matter what OS you're using). Make sure you defrag your HD before attempting to repartition as well. Just keep in mind that you're using a Microsoft product, and MS isn't built to play nice with non-MS products. There is some risk.
Personally, I have no use for Microsoft and haven't since switching to Linux over two years ago. I'm forced to use it at the office, but that doesn't even stop me from doing work at home. Many Linux apps are equipped to import MS data files and export them back. So, no one at the office suspects that I'm not running XP at home. Well, other than I have nothing to complain about (computer wise) at the coffee machine in the morning.
If I were to do dual booting, I'd simply get a second hard drive, leaving my XP drive alone. I'd then install Linux on that hard drive and set my boot-loader to include the XP drive at start-up time.
If you were to re-partition, I recommend either one of these approaches:
1- I'd use cfdisk to repartition rather than QT-Parted; both of which comes with Kanotix. cfdisk does not have a GUI (graphic user interface), but I haven't had any issues in using it. QT-Parted will give me "weird" feedback from time to time and I'm not all that comfortable with it when that happens.
2 - Mandrake and ALT Linux (from my experience) have the best GUI interfaces for repartitioning at install time. Much simpler for a novice to understand.
I know this is a long post, but I hope it's helped in some way.