Game Emulation

Ever wanted to play that old NES game that isn't around any more? Don't your parents want to waste money on your silly Nintendo games? Do you not have a console? Then you have just been bathed in mythical light! Game emulators are the way to go!
An emulator is a program that mimics the functions of a system using another one. In this case we're talking about a console (like a Xbox) or hand-held (like a GBA) to a computer. Game emulators run on these things on ROMs (Read Only Memory image). While emulators themselves are squeaky clean, a commercial ROM is illegal. Home-brew ROMs are clean.
 Lots of people use emulators for an equal (or greater) amount of reasons. Most people will play emulators for a few basic reasons; it's free, the game isn't sold any more or you can take that PS3 game around in a laptop. Of course there are the basic downsides as well. For one thing, you can't really lug your desktop around (sure you could a laptop but it's not the same) for hand-held games. Also, many of the games you might be itching to play are, as I said before, illegal.
Seeing as most people disregard the "illegal" part, emulators are thriving. A few have become well known on the net.
Some good emulators:
No$gba - Nintendo DS and GBA. Setup may confuse some.
VisualBoyAdvance - GBA, GB and GBC. Keys can jam on action games.
BoycottAdvance - GBA. Can't play as many games as VisualBoy. No speed multiplier.
Project64 - Nintendo 64.
DeSuME - Nintendo DS. No speed multiplyer.

There are a lot more. I just don't know them. C:
Check out:
The Emulator Zone
Cool ROM
Dope ROMs

Anyone have anything to share?