TheGameCunter

VisualBoyAdvance (commonly abbreviated as VBA) is a free emulator of the Game Boy, Game Boy Color, and Game Boy Advance handheld game consoles as well as of Super Game Boy and Super Game Boy 2.
 
- Description from Wikipedia Page.
VBAdvance 1.8.0 is the most recent version for the GBA Emulator. (last version: 2005) 

FCEUX is a Nintendo Entertainment System (NES), Famicom, Famicom Disk System (FDS), and Dendy emulator. It supports NTSC (USA/JPN), PAL (European), and NTSC-PAL Hybrid modes. It supports both Windows and SDL versions for cross compatibility.
The FCEUX concept is that of an "all in one" emulator that offers accurate emulation and the best options for both casual play and a variety of more advanced emulator functions. For pro users, FCEUX offers tools for debugging, rom-hacking, map making, Tool-assisted movies, and Lua scripting
FCEUX is an evolution of the original FCE Ultra emulator. Over time FCE Ultra had separated into many distinct branches.
- Description by the official website
FCEUX 2.3.0 is the most recent version for the NES Emulator. Support the dev team over here: http://fceux.com/