Welcome!!!! Wang-Tang!
which emulator you want depends on which console you want.
the easiest consoles to emulate at the moment are Gameboy/GBC/GBA, NES, SNES, most Sega consoles, and Nintendo 64. NDS and PSOne are also reasonably easy, though PSOne emulating requires a bit of configuration and some NDS roms are in foreign languages if you're using an emulator. they both need at least 512MB of RAM as well, i think.
now, i will list the console and then the best emulator:
Gameboy/GBC/GBA -> VBA
Sega Genesis/32X/Master System/Gamegear/Sega CD -> Kega Fusion
NES -> Jnes i think, but i don't emulate NES...
SNES -> ZSNES
Nintendo 64 -> Project 64
NDS -> NO$GBA
PSOne -> ePSXe
other emulators for PSP and PS2 are still being developed, so i wouldn't suggest trying them out yet.
hope this helps