Well I went into my basement and found a homebuilt computer desktop that was made around 2000 A.D.
What are some cool or useful things to desolder or salvage from computers?
I have rams, hard drives, CD drives, motherboard, power-supply, cables, heat-sinks, graphics card, modem.
I have a list.
Amp circuit from CD drive.
Hard drive platters
Look for memory back-up capacitors (I hope)
the large heat-sink
power supply
At the end of the weekend I will post what I got 
with pictures.
Old computers have some cool switches and LED's in them that are pre-wired and all kinds of screws that can be used for other projects.
Remember to scavenge all the little rectangle jumpers from everything. Those are always handy to have around.
If you can manage it without burning them up, the motherboard has a few voltage regulators on it as well as many capacitors. Also, try and get the multi-pin headers off the boards. Those can be useful for a lot of things. Of course, there are all the ribbon cables from the drives. They can be used as-is or cut apart to use for different projects.
Well, that's all I can think of right now. I have a major sinus headache right now. :o
One of the most useful parts is the power supply. If can be modded to become a general purpose bench DC power supply that provides several useful voltages at significant current capacity.
Lefty
Fan's, chipset heat sink
Don't forget the neodymium magnets in old hard drives. Best fridge magnets ever.
Computers probably are not the best places to salvage parts. But you can definitely de-solder those through-hole caps on the mother board and possibly get a few useful ICs (like RTC chips, etc.)
As retrolefty said, power supply is probably your best bet since there are a lot of discrete components inside. But I have found that some manufactures use some sort of "glue" on components in PSU, presumably making the PSU more robust, but makes salvaging parts more difficult...
Best fridge magnets ever.
Haha maybe not to be used if you ever want to get them off your fridge again!
I got some small neodym magnets from dealextreme, awesome fridge magnets!
They can easily hold a bunch of papers each... plus a key, and other stuff you got in the kitchen...
Yeah get the little ones (3mmx2mm circular ones or something)
Very useful for projects using hall effect sensors/reed switches etc.
Good for box catches too but don't use hard drive ones if you ever want to get the box open again ;D
Mowcius
Strip the ethernet + magnetics socket; backup battery holder; and if it really is from 2000 that'd be prior to the capacitor plague so you could strip all the electrolytics with which to re-cap a more modern board that has suffered from exploding bad caps.
I use a power supply for 12v and 5v, you can quit all the wires you dont need, but be carefull, inside the power supply box are big capacitors and if is turned on, manege high voltage inside.
Maybe you knew that, but just a reminder.
The screws, wires, jumpers, HEAT SKINS, are usable too, but im not using them.
I desoldered a bunch of surface mount chips from an old computer, then looked up all the chip #s.
I don't even have a good enough soldering iron to solder surface mount (xmas?), but I still salvaged those parts.
I haven't done any hacking yet, but here's my plan, feel free to add:
Case
metal - chasis for future robot
Power Supply
Not going to hack it. My new bench-top power supply.
CD Drives
laser - for fun
motors - no idea yet
amplifier board - for amplification
metal case - for enclosure
LEDs - to add to my collection
Motherboard
Processor - short circuit and make it into a hot plate
heatsink - no idea yet
female ports - no idea yet
capacitors - to add to my collection
RAM - to sell on ebay... no idea yet
Coin Cell - for my incoming RTC chip
Piezo - no idea yet, is it a piezo? (Top right corner of picture)
Slot Headers - no idea yet
Modem
Speaker - yes that annoying dial up sound - for an annoying project
5V Relay - to play with
Ethernet connector - no idea yet
Crystal - no idea yet
Graphics Card
IC Socket - no idea yet
IC on Socket - find out what it does
Crystal - no idea yet
Sound Card
What can I do with a stand alone sound card?
Can I amplify music?
Female ports
Hard Drive
Motors - to see if it is stepper
Shiny Platter - attach to fans, shine laser on, make a laser show
Magnets - for fridge
Enclosure - no idea yet
Look at what each IC does
Miscellaneous
Screws - for enclosures
Ribbon Cables - no idea yet
Jumper Cables - for Arduino
7 Fans - Other than laser show, what to do with 7 fans?
Switch and LEDs (front of case) - no idea yet
I was hoping to find some high farad capacitors. Well.. they're not in computers.
Any other suggestions for how I should use the salvaged pieces or what other pieces I should salvage?
;D
You could use them to construct an authentic circa-2000 AD computer.
lol
CD Drives
CD drives usually have some interesting high-strength magnets in them as well. Frequently a small doughnut shaped on to help clamp the CD to the spindle motor, and two small rectangular magnets in the optical head assembly (for fine positioning of the lens in two axes...)
And gears. Although it seems to be pretty uncommon for found gears to ever be useful for anything else 
CD drives are one of my favorite things to take apart.
But I should stop now and actually get around to doing something with the pieces...
hai
In my expierence only some few componets is useful. :-[
Jeckson
Drill a hole in the center of the hard drive and put a clock movement in the back.
Add some hands and you have a seriously cool clock.
The Modem is essentially an Ethernet module. It doesn't have a lot of pins, so I'm going to try to interface it with the Arduino.
Maybe it could be a suitable replacement for the Ethernet shield!
And nice ideas. I'll try building a circa 2000 A.D. computer.
Seriously what do I do with 7 fans? :o
Seriously what do I do with 7 fans?
Miniature hovercraft?