Want to see unix, install openbsd, its not legally unix, but concepturally, (and historically) it unix, Linux is nothing like unix, unless your comparing it to windows. Linux is very refined and isn't confined by the unix specification. Its a double edged swords, its easier to use and maintain but not as stable and secure as unix. Nor as powerful or light weight(not always the case but with openbsd in mind the above hold true, not so for actual LEGAL unix, see SCU, Solaris, MacOSX)
1. Yes, easy way, unetbootin
2. I use all kinds, on my desktop, Kubuntu cause its the best version of KDE 4 in my opinion, I love the way they compiled it and apt is really nice on a desktop system, which is inheriatly plagued with security flaws and buggy code due to the complexity of making things pretty and user friendly. Though OpenBSD with fluxbox can be just as nice but takes alot of work up front and well too much too go into.
3. KDE vs GNOME, gnome been the same for YEARS i mean YEARS like 4 or 5, kde just recently changed for the first time IN YEARS. KDE is based on qt which is currently owned by Nokia. Gnome is run with GTK (gimp tool kit) which is completely open source. QT isn't free for commerical use, GTK is. KDE is pretty, but still not completely stable, gnomes a little more stable and better integrated into ubuntu. I just like the way it looks. I hate the ubuntu brown, its amazing ubuntu is as popular as it is considering how ugly it is by default(gets better every year, they just won't let go of the brown)
4. Linux is better on the desktop, it could go either way on the server depending on the intended application and hardware
5. Sudo is currently developed by the openbsd guys. Whats not to love, those guys know their security, one hole in 8 years, that ******* incredible (that i know of)
6. install it, run wine or winecfg it will automatically populate your home directory with all the files it needs, your windows programs aren't installed with root privledged their install in your user folder. You can also compile the latest version, in ubuntu/debian you can easily resolve your depencies with a simple command
sudo apt-get source wine
or just install the version they maintain
sudo apt-get install wine