Organization via spreadsheets.

Docs/drive is perfect :)

Google Docs, one tab for each Bundler plus two other tabs (one for misc, one for misc bundles), and another tab to try to keep track of what I have available on one page (I've failed to keep that one up to date, so it's almost useless now).

I have a shortcut to it in my browser with "keys" as the keyword, so it's easy to pull it up real quick.

[more_info_edit]
On the bundle pages, I have the main bundle page URL at the top, profile link when applicable, notes on what email(s) I used and such.
Then each bundle release on a new row with a few columns:

• intended recipients (me, SteamGifts, friends, etc.)
• Bundle name and contents (also with icons like ♫ for music, + for DLC, ► for videos, etc.)
• Steam keys
• direct URL and/or misc info
• Desura keys
• misc keys or whatever
  [/more_info_edit]

Excel + Dropbox = win. I use it for my work and uni projects.