There are times when the command line just can't be beat. Often it does things much faster than the GUI. For example - clearing the IE cache - while that takes about 3 hours using the GUI, and often causes explorer.exe to crash (even if it's empty!), the cmd line does it easily.
Then there's a few other things which I prefer to do via cmd line - such as ftp - although I'm not saying here that it's any better than any of the ftp programs around.

Also, my work uses Novell, which means that I am supposed to log in each time - but by having TweakUI log me into windows automatically, that bypasses one login step - then I use the "net use " command (through an autoexec batch file) to log in to the Novell servers (a command I've well remembered)
Although it is rather annoying that it doesn't work in Win98, which is what some of the computers at my work have.

But the main reason I use the command line is not so much for Windows purposes, but for shelling to another OS (eg UNIX), whether it be ftp or telnet, or if I boot with Linux to change Windows accounts that I've forgotten the passwords for (a lovely little trick that Microshaft are yet to disable)

I am a loud man with a very large hat. This means I am in charge