The only good video editor for linux I have used is payware - the
Mainconcept editor. It is also the only one I managed to install on my
linux (Kanotix) installation. I have now changed to Mepis and nothing
seems to install but that is almost certainly my lack of linux knowledge.
There does not seem to be much free stuff for Debian installations.
One free editor I have tried is LiVES but only running off the Dynebolic
live CD. This was painfully slow to use and would often hang while
rendering but might be worth a try.
http://dynebolic.dyne.org/
A good list of linux video stuff can be found here.
http://www.linuxsoft.cz/en/sw_list.php?id_kategory=19
Another possibility is trying to run VirtualDub under WINE - if you can get
WINE to install / work