I've got a few "classics" that tend to stay with my kits and gear piles over the years.

1. A stainless steel Flask.

Right now an 8oz, single walled stainless flask. I like it filled with an over-proof whisk(e)y. Right now, my favorite is Booker's Bourbon, which is ~126 proof or 63% alcohol. It easily lights on fire, it has a high enough alcohol content to be suitable for wound sterilization, and, unlike Bacardi 151, I find it to actually be borderline drinkable neat. crazy Plus, it's made right here in America (the Bourbon, not the flask, unfortunately).

2. Simple white cotton bandanna

Not much to say about this one, other than they are about as simple and multi-purpose as an item can get.

3. 550 Paracute cord

Again, not much to say. It just works.

4. Bic lighters

I don't smoke, but I have Bics throughout my packs, jackets, vheicles, ect. They're cheap, they usually work reasonably well, and I can loan them out (or, more often, give them away) without breaking the bank.

5. Leather gloves (like suede cowhide gloves)

I've got plenty of pairs of modern polyester/neoprene/Kevlar/super fiber gloves. But, when it comes to general work gloves, I still keep finding my way back to good old leather gloves. They feel good, they don't melt with heat, they're reasonably cut/abrasion resistant, and they cost less than $10 a pair.

6. Spiderwire braided fishing line

While not really that old, I've been in love with this stuff since it came out. I use it for fishing line, sewing thread, thin string, whatever. From their current stuff I like the "Stealth 20lb moss green." It's a good combo between strength thickness, and ease of knot tying.

7. Moleskin padding

Blisters can very quickly turn a fun hike into a painful hike. Sometimes a little bit of moleskin is all I need to keep on trucking. It's simple, inexpensive, and I find it works great.

8. Fisher space pens

While not the best writing pens I've ever owned, they do tend to be very durable and they continue to write at times other pens fail.

9. Sharpie markers

Same as above, they're simple and they usually do what is intended of them. Can't really as for much for than that. On a side note, I prefer the Industrial version. The ink formula is a bit better.

10. Swiss Army Knives (preferably Victorinox)

I collect knives, in fact, at last count I was well over 200. However, even with such a large collection to choose from I've still got a few Swiss Army Knives that make their way into my pocket on occasion. I don't leave home without the Swisscard in my wallet either.

11. Other traditional American/German slipjoints/lockbacks.

Along the same line as the Swiss Knives, I've got a few other traditional slip joints and lockbacks that find their way into my pocket. These are made by companies such as the former Imperial Schrade cutlery company, Queen cutlery, Case, Buck, and Boker. I have a soft spot for these kind of knives, as they're what my father owned, my grandfather carried daily, my uncles carried daily, my great grandfather carried daily, ect. In my mind they represent the hard work and determination of bygone Americans. Their toil is what allowed me to live here today in reasonable comfort.