On disk? You can still buy those things?
I give mine a few spreadsheets, one for all my trades, one for dividends & distributions, and one with all other stuff. I email them as PDFs, although they sometimes come back and ask for the XLS files (easier for them to do sorting, etc).
Haven't looked at the Excel spreadsheet thread, but each of mine just have the basic information required by the accountant and maybe some extra columns for my own use. The data for them is generated by the portfolio software I use, a program I developed myself.
Then I also send them any physical paperwork they need, like dividend/distribution statements, bank statements, etc. (I use Express Post for this - I never actually visit my accountant).
Cheers,
GP