My dear Sanket,
I think I agree with Philip that its absolute madness using X as root. As for peoples' habit, change the bad ones!
Another thing, if you're not comfortable with sudo, quit using Ubuntu!
And Anurag's comment is perfectly right. Use bash completion. If that's not your way, here are the ways to use bash's in-built completion facilities. Mind you, this works in emacs mode. Type 'set -o emacs' to make sure you're in emacs mode in bash (bash also has a vi mode, but even though I only use vim as a text editor, I found emacs mode easier on the bash command line).
Esc+! = Command completion Esc+@ = Hostname completion Esc+$ = Variable completion Esc+/ = Filename completion
Using Ctrl+x instead of Esc will list all the possible completions, just like TAB-TAB.
HTH, Sanket
P.S. I think a seminar on bash's advanced features would be quite nice at a LUG meeting, before a seminar on shell scripting ;)