lshw is a great little tool for extracting detailed information about the hardware on your machine. You can run it as a regular user, but it will only report paritial information, so it should ideally be run as the super-user (prefixing it with sudo or su as per your distro).

A basic report will flood your screen so either pipe the output to a text file:

lshw > hardware.txt

or a formatted HTML file:

lshw -html > hardware.html

For a compact listing of your hardware, try:

lshw -short

Adding the -C switch allows you to find detailed information by device class. So for details about all installed disk drives use:

lshw -C disk

and for your network's hardware and its capabilities:

lshw -C network

You'll find other classes listed in the lshw -short command.