I can help with the emulators but not the ROMs/ISOs, due to legalities and being against site rules. Google will help, just be smart with your downloads. (Watch for the files types the emulators ask for)
However, I can help with the emulators.
For a very strong general use emulator that I use, and many use for being a very accurate emulator is Bizhawk. It's essentially a plug-in client with compatibility with many consoles. I primarily use it for N64 because of how very accurate it is. https://code.google.com/p/bizhawk/
Project 64 is also very popular and very strong for N64 specifically. 1.7 is the very accurate version, while 2.0 is over preforming so it's not recommended. http://www.pj64-emu.com/
For strong overall Gameboy/Gameboy Colour/Gameboy Advance, Virtual Boy Advance works well, the installation is filled with bloatware thought because of it's popularity. http://visualboyadvance.net/
Nintendo DS only has DeSmuME as a strong emulator. It's accurate and well made. http://desmume.org/
Playstation/Playstation 2 I like to use PCSX2, it's very strong, a lot of plug-in support. It's difficult to get it running because you need to acquire the appropriate PS2 BIOS also, and that is up to you along with the game ISOs. http://pcsx2.net/
Gamecube and Wii are handled by Dolphin, Logan uses it for his Wii. It's really the only reliable emulator for these consoles, with a lot of plugin support and has a very accurate "working games" list. http://www.dolphin-emulator.com/
PS3, Xbox, and Xbox 360, as far as I know they can not be emulated, if not well, at all. You're best to acquire the consoles and games legitimately in those cases. (PS3 has softmod work arounds for that but I can't help with that either)
Other emulators that get the job done, incase Bizhawk is too much of a handful for you
Super Nintendo/Super Famicom
Lsnes is highly recomended for accuracy http://repo.or.cz/w/lsnes.git
Zsnes is easier to use, has a nice UI, but isn't as accurate http://www.zsnes.com/
Nintendo Entertainment System/Famicom
Jnes works http://www.jabosoft.com/categories/1
Nestopia works too http://nestopia.sourceforge.net/
I hope this helps you out, and if any others have help for you I'm sure they'll pitch in. I can also help if you have any issues setting any of this up, within site rules.
*If you need help with recording, if that may be of your interest I can help you more on that too, since I use these primarily for watching/toying with TAS and other speedrunning glitch discovery.