Currently using the Logitech F710 Wireless Controller. I haven’t finished setting everything up yet, but it’s working well for the menu and GBA.
Just bear in mind that many devices see this as an Xbox 360 controller (including some PC games) – BUT the button mappings differ, so button mapping this thing may be a little counterintuitive.
It’s a great controller. A bit hefty, but has great grip and a good button layout (akin to the PS layout). It’s also the best PC gamepad you can buy – even Valve endorses it!