I hooked up a tablet (jailbroken ipad but android would work as well or better probably) with emulators on it to a wiimote with classic controller (bluetooth connection). Great Nintendo dpad, screen that's big enough to see what's going on but not as painfully high-res as a pc screen, and it's easy to turn on and use once setup. Currently playing Super Metroid for SNES.
Worth trying if you have any interest in older games, a HUGE leap over playing on a PC or modern console with a port using a controller or keyboard. The classic controller somehow works really well, it must be the flat buttons and good dpad. Perhaps XBone controller will be better, I heard it has the "+" dpad.
I also recently finished a MAME cabinet build (full-size) which is nice for arcade games, but not so great for non-joystick designed games. Neo-geo I can get away with, esp. fighting games, and some 2600 stuff, but the rest has to be switched to 4-way mode which takes too long to be practical. (You have to get inside the machine and have 2 people do it)