Which FS should I install?
The default is ReiserFS, but apparently ext3 is better.
What's "X"?
you aren't allowed to ask difficult questions..
You do NOT need to know this, but it's for your own information.
The graphical interface on Linux is split into two pieces, a client and a server. X is the server. It communicates with the back end hardware, and contains the drivers. It keeps track of which programs are running. It listens on a standard port, and when the X client connects to it, it sends it what stuff is supposed to be on the screen (windows, etc). The client, which is called a "Window Manager", decides how to display the windows, and sends things like keystrokes and mouse movements back to X.
What you DO need to know: when you have Linux installed, it'll boot into a command prompt. Type "startx", and press enter. That starts the X server and the X client, and life is good.
I can just put ANYTHING I want for the hostname and the domain name and what if I'm planning on using two ways to connect to the internet? At home, I use my DSL box and at places with free Wi-Fi, a NIC.
hostname is just the name of your computer. Pick something creative. Domain name doesn't matter, I've never seen it make a difference; I use javaop.com because it sounds good.
If you're going through a router at home, or through cable, it's easy. Just tell it you're using dhcp, and nothing else.
If you're planning on using wireless, that might be a little trickier. Slackware automatically installs wireless tools, but I prefer using my own shellscript:
http://www.javaop.com/~iago/home-wireless.shOften, wireless cards aren't recognized by default. My Microsoft wireless card works fine by default (weird, eh?), and my Intel one doesn't. You may have to do some searching for wireless drivers, but most common cards have them somewhere. Worry about wireless later