MAME is the king, but it doesn't hurt to mix it up from time to time

Ok so here are two great console emulators that use Kaillera for online play (P2P/regular server) just the same as MAME does. You can find them easily through Google:
SNES9k990z (SNES emulator)
Project64k (Nintendo 64 emulator)

As I just mentioned, these emulators use Kaillera just the same as MAME does. If you're unfamiliar with how to use/set up Kaillera then check out the following link because Hiero wrote the book on it a while back:
http://www.mameaddicts.com/phpBB3/viewt ... ?f=9&t=316
Although P2P is two players maximum, it should always be chosen over a server when you only have two players. The gameplay in P2P is lag-free.
I've found the most fun so far is while playing the Mario Kart and Mario Party games, but keep in mind that the libraries of games on these consoles are huge so don't feel as though you should only be playing Mario games!

Lots of single-player fun to be had as well.
This thread will be updated from time to time with more console emulators, screenshots from online sessions, and anything else that seems appropriate such as top games lists, solutions to common problems, etc. Please feel free to contribute.
Please keep all related questions, etc, in this thread. This is an arcade forum, not a console forum.