Curious - what custom columns are you creating/using?
I just last week updated from one of the 06.xx versions to 0.7.6 and am now playing with user defined columns. At the moment I am adding columns for:
Source (ie. where purchased/obtained from) such as Amazon, Fictionwise, MobileRead, etc.
Original Format (ie. the original file type before conversions): lit, mobi, azw, epub, etc.
Read (Yes/No)....though I may change this one so I can populate it with DNF (did not finish) or Reading (current) in addition to Yes or No.
I was using regular tags for these but decided I'd like sep. columns for them.
What custom columns is everyone else using?