Emulators for Android?

[MrSocks]

Good day to you,
I am aware of large number of different emulators on android scene, and I was wondering, which emulators are definitely the best for the major consoles such as N64, SNES, NES, Gameboy Advance, PSX and so on? And do you know about any amazing emulators for old PC games such as dosbox, ScummVM and so on? Simply put, a way to play good old games on Nexus 7, which would the phablet be able to run?