You may want to consider assigning your projects a priority (1-5). I know this isn't kosher GTD, but asking me to "intuit" my most important Next Actions from a list of 500+ just wasn't going to cut it. Now I have 5 Next Action lists -- I intentionally look at the Priority 1 list first, and if nothing catches my eye then I'll move down the priorities accordingly.

Also sounds like you may need to spend a day plowing through a lot of mini-tasks... all those lightbulb changes and quick email responses really add up, and it's so nice to get them out of the system altogether by devoting a day to the mundane but eventually necessary.