I am impressed by your spreadsheet storm, and its a very good idea regarding insurance issues.
I have two spreadsheets files, one for my regular comics/bande dessinées collection (with tabs for Mills/Moore/Mignola/Miller/whedon/Miscellaneous and francobelge), and another one for my Conan comics collection (two tabs, US and French).
I usually only note the title and publisher (and print # for Pat Mills stuff). I keep all my invoices for insurance purposes.
My non regular collection (i.e. deluxe/absolute/limited ..) is referenced in these spreadsheets amongst the rest but to the question How-Do-You-Track-Your-Collection?, my response is "with my blog"!