To the first question.. Finding out what hardware is in a system. you can open a shell and use the lshw command.
To get info about ALL the hardware in your system use lshw by itself with no parameters.
user@it-etch:~/$
lshw
if you want JUST the CPU information it would be
user@it-etch:~/$
lshw -c processor
To see what versions of system monitor are installed on your systems you can use apt-cache policy
Code:
user@it-etch:~/$ apt-cache policy gnome-system-monitor
gnome-system-monitor:
Installed: 2.22.3-1
Candidate: 2.22.3-1
This is the version on my Debian Lenny box, and I do have the system tab available.
And if you are really stuck on GUI's you can install
gnome-device-manager, which will appear in your system menu as "Device Manager"
Ubuntu is based on snapshots of Debian sid (unstable) I believe, so it will actually have newer packages in it than Debian stable.