Recommendations for emulators to use with mala?

[CpCaveman]

Ok so i`ve hit THE wall and just cant bring myself to finalise my cab ( well its game over then aint it, and i cant see me building another one, no point got what I wanted )  just cant bring myself to shorten a few wires and screw a few pieces into place, thought carbon fibre vinyl was OTT but now I`ve even been thinking of stencilling in clear UV paint and changing my led strips to UV ones, adding shelving, and overdoing everything to the point of insanity just to drag it out, havent done that yet but its getting close

 Anyhow to the point, I`ve seen a lot of multiple emulator talk, so can anyone recommend emulators for the following systems that are (virtually) trouble free with mala (I`m sticking with it as its a doddle for an idiot like me ) ?

nes
snes
master system
megadrive/genesis

hand helds
gameboy/color/advance
gamegear

would prefer ones that save games if they can

I found one of my old HDs with shedloads of roms which I`ve never used, dont know much about actual emulators, and its something i can do without making my cab look like a kids box whose just been given a bunch of his favourite errr... umm... pokemon? (is that what they like? should pay more attention other than just nodding ) stickers. Would also be a handy topic for others too i fink 

[bmanbdaman]

nes, gb, gbc, gba - mednafen, save games work, key remaps work (my cab uses 1-save, 2-load for most everything)
gg, sms, md - Fusion, save games work (Function keys or mouse), cheats work, I use a mouse and disable hotkeys, could use AutoHotKey
snes - zsnesw, save games work by remapping keys, cheats work