Due to my general lack of consoles I often play old (up to ps1 and N64) games on my pc so i thought it would be a good waste of my time to make a list of my favorite emulators to help anyone out there who wishes to start doing so also. It is particuarly helpfull to have emulators when you either want to play a game that you once had but threw away either the cartrige or the console or are otherwise unable to play it for various reasons. To the best of my knowledge, owning digital copies of a game is legal 'as long as you own' a copy of the original so there should be no need to worry about such problems, also there are many rom sites around the internet (I wont link any for various reasons) but rest assured they are easy to find. All the software below will be freeware and most only take up a few megabytes (if that) of disk space. I will update this list with new software as i find it or on request by anyone who wishes to share their own personal favorites.
Anyhows:
PS1: ePSXe
http://www.epsxe.com
This is by far the best ps1 emu that I have been able to find, although it is a bit complicated to set up at first there are many FAQ's to help you do so. It supports many games and there is a huge number of graphics and sound plugins available to customise it exactly for you needs.
Nintendo 64: Project 64
http://www.pj64-emu.com
I have only downloaded this recently so I am not aware of any bugs that may occour but this is regarded as one of the best '64 emulators out there. Its simple to set up (took me about a minuite to dl it and get it running) You get great qualitly on it too, I constantly get around 50-60fps at the highest settings.
Nintendo DS:
http://www.nogba.com OR http://www.desmume.org
For ds emulation I use either of these two, I find they are both as good as each other, most ds games are compatible although there are some compatablillity issues. Also ds emulation can take its toll on some lower end pc's, occassionally i get some lag while attempting to play some games with too many background programs.
GBA: VisualBoyAdvance
http://vba.ngemu.com
Simple, easy to use, nuff said.
Nintendo Entertainment System (NES): Nestopia
http://nestopia.sourceforge.net/
A nice little emu for anyone out there who wants to play the original Zelda, Mario Bros and all the over classics, it has several cool features including netplay (I personally have not been able to try it out yet but i am led to belive it works, if it dont, bite me.)
*sighs* this is all i can be bothered to do for now, will update as soon as i can be bothered/remember i posted this thread.
Feel free to ask any questions and have fun! (not that anyone really cares :3)