In my campaign, I use a system of cards. This has taken quite a lot of my time (and ink) setting up, but it really makes for a memorable system where items don't get misplaced.
The basic card I use is a nine to the page card. These fit nicely into the baseball card sized sleeves you can get at Wal-Mart. (They're cheaper than what my FLGS carries for Magic, but they're not acid free and all that fancy stuff.) Each character gets a folder which has a full-page sheet for the character sheet and several 9-slot sheets for items. I printed labels and stuck them on the 9-slot sheets so you know what is in your head slot, what is in your belt slot, what is your primary weapon, what is your backup, et cetera. This makes tracking magic items easier and makes it cake when someone else has to run your character.
Magic items all get these 9-per-sheet cards, from potions on up to powerful weapons. I also use the same size cards for masterwork items.
I have somewhat smaller cards for ammunition and grenades. This is mostly because the ammunition card fits in the sleeve nicely in front of the weapon card, and you can still see the details of both weapon and ammunition.
For treasure items, I have smaller cards (closer to business card size) that have the details of the item. I also have cards for money. (Similar to the "Fantasy Money" product, I have cards for larger amounts, like 50 gold coins. I have different cards for the monies from different countries, so the players can keep track of what they really have.)
I'm experimenting with sleeves that are for photos for the money. There are some 4x6 pockets and other sizes.
The idea is that you have either a pocket or a sleeve for "at home" or "on the ship" (they own a ship) or "in the bag of holding" or wherever isn't on your person. They'll probably end up with a folder for the ship to keep cards for things stored on the ship that aren't part of any one PC's inventory.
This really helps keep track of things. You want to drink a potion? Give me the card. You want to spend money? Give me the card. Lost the card? You lost the item. If I want to know who has something, I just ask for the card. (This became important in a campaign years ago before I started doing this when they had a rod of healing that got passed around so much that no one knew who had it anymore.)
I admit, I also like this because it has kept certain players I used to game with from writing down extra stuff on their sheets. I started looking for this method when I had a player who was in a college group where I had no choice who I took who used more healing potions in one battle than I had given out all campaign.
If you want to save some time on card creation, I know TOGC makes a Complete Item Card product. I custom designed my cards because I wanted slightly different information and because I found developing them in Adobe Pro' to be fun.
I print everything on cardstock and I have a Firskars (sp?) paper cutter that make short work of the cards. I have several boxes designed for Magic cards that I use to keep things organized. (I also created dividers. I'm that obsessive about it.)
The beauty of it is that once you have it all, you rarely need to make new cards -- just for new magic items or new treasures, or if you add a currency.
I also like the suggestion of someone on these boards that when its time to search bodies, you throw out envelopes with what each creature had on them. (I don't bother with cards for bits like "piece of string", "shiny pebble", and the like.) Whoever grabs the envelope starts searching the body first.