Monitoring Usage

I run a couple of personal servers for a group of friends - we all utilise the servers for IRC shells, web development, web hosting, irc links etc. I don't run any web hosting software or any such like software because I don't like how the designers never understand Linux. Anyway - until now I have not performed any user bandwidth or disk space monitoring. I can't seem to get the quota system to work (and I don't really need it) - but what I would like is to monitor user bandwidth and disk space usage.

Is there any nice tools out there that does not require SNMP to report how much bandwidth and disk space a user uses in a day or so?

(my plan is to run a cron which will e-mail me the stats every day).

Cheers!

X-Posted to debian