Apple's Black Stick
As Command-Tab reminds us today, Apple's technical support manuals consistently refer to this mysterious tool for performing tasks. It's available from Apple via their normal ordering channels for like $10 but you can easily find it for sale for a fraction of that cost. We always had a few of these lying around. A non-conducting and non-marring plastic tool can be a remarkably handy thing to have around when you're taking apart PowerBooks.
Why iMac Cases Used to be Translucent
Several years ago, I was working in the field on a slot-loading iMac. I don't recall exactly what I was doing, but probably replacing the modem (as there was a spate of modem failures). I had flipped the blue beasty upside-down and taken the bottom casing off to get to the logic board and modem assembly (it's connected to the I/O ports). While removing the modem assembly (or perhaps it was while removing the silver EMI shielding), I accidentally dropped a screw down inside the translucent casing. Oh crap! Anyone whose taken the slot-loading iMacs apart (like to get at the video analog board) knows that removing the top (colored) casing can be a royal pain-in-the-ass. I really didn't want to have to completely disassemble the iMac just to retrieve this screw. Damn! There must be an easier way! Fortunately, I typically carried with me in my bag, a package of those 10-12" long pull-ties for binding together cabling. I also carry with me in the winter months some chapstick. I put some chapstick on the end of one of the pull-ties and went fishing. 30 seconds and one still-assembled iMac later, I had my screw back. Heh.
I bought one of these after the above incident.
Your Best Friend, the Multi-bit Screwdriver
The absolute best compact screwdriver out there is actually made by Compaq for its technicians. I've had this driver for a really long time and its been a trusty companion with me on countless service calls. It comes with the Torx-8 driver for those screws that Apple seeed to use in almost every single machine they shipped between 1997 and 2004 (still are, for all I know).
Your Other Best Friend
I can't count high enough to count the number of times my Leatherman Wave multi-tool saved my rear while on site, from whittling down the plastic power buttons on the first slot-loading iMacs so they'd fit better into the molding so they machines wouldn't keep putting themselves to sleep, to the tool of last resort in deftly extracting a stuck Zip disk from a dying Zip drive, to carefully stripping a wire with the scissors tool.
Self-explanatory. Keep with you a small bag of screws of many many different sizes, especially those used for securing hard drives or logic boards.
OK, techies, what tools, tips, or tricks do you have? Maybe you've rescued a HD from complete data loss by freezing it in zip-lock bag (I have, on several occasions), or maybe you've your own MacGyver tech support story.
Update: I've linked the picture to the Threadless.com T-Shirt shop. I couldn't remember where the image came from (it was among the many thousands I have squirreled away). Thanks for the info.