So after playing around for a while with the Pi I got Retropie set up (very easy), managed to plug the pi into my router so I could get wifi going via putty commands and I've copied over a few roms. Snes and Mega Drive are working well, others are either not starting and bringing up error messages or look like they're starting but then go straight back to the menu (Dreamcast, Neo Geo, GBA). Guessing I need to download BIOS files for those. Will check out the wiki and see what it says, do a little playing around.