Awe people - here is my conky config for your enjoyment. First things first, you must edit the config file for your system.
Possibly your interface is eth0 - where mine is eth1. Replace all occurrences of eth1 with your interface.
Then install vnstat - you'll find it in synaptic - and set it up with your interface: sudo vnstat -u -i interface (where interface is eth0 or whatever). It will take a few downloads to build up it's database.
Please note the following:
1: I put the gmail.py script in my ~/scripts directory - where you should edit the file with your information.
2: I use conky v1.4.7.
3: If you don't have a 1280 by 800 display and you're a bit lazy - I have included a modified v4 for a 1440 by 900 display. I'm not sure how it will turn out - because I don't own such a display. So please let me know how it looks - also if you have made it suite your display of any size other than 1280 by 800, please send me a sceenshot plus the conky config so others can benefit.
If you have any cool ideas to add - let me know. Peace
(Btw the screenshots are in order: v4 - v3 - v2. All files are included in the conkyv4.tar)