Great thread! Although, I'm fairly new to ViM I thought I would share my personal favorite. I'm Not sure if I overlooked this one, so I apologize if it's a duplicate.
while in a document, just type a number and press Enter in order to skip that many lines from your current location - no need to preceed with colon:
100 Enter #skips 100 lines from current location
20 Enter #skips 20 lines from current location
I think you get the drift.