Great method I was shown a while back and use to this day if working by yourself:
Get a big legal pad of paper. Get a smaller legal pad of paper.
Walk around the building / tower sites and jot down all the things you need to do on the big legal pad. Add anything anybody "drops by" to tell you what is wrong to the big pad.
Each day, sit down and transfer items to the smaller pad. That's your to-do list for the day.
This is also great because if management/ownership wants to know what you're doing, you just hand them your legal pad. Or type it out and email it.
If working with a team:
Big white board. Divide to three sections: In progress, upcoming, and wishlist. Each person has a different color marker. Move around as necessary.
Another team tip: Use Google Apps. You can add each other's calendars, use Google Docs to store documentation on projects that you can access anywhere (in building or out).
As for the "stuff", I think CW said it best. If it hasn't been used in 6 months, get it out of your office. Drag it to a tower site, sell it, etc...