Emulator newbie looking for advice

Hi guys, glad I found this place.... i'm an old gamer..... back from the 80's 90's ( 40 years old :( ) and just about to rediscover the old games I grew up with.
I'll have a look around the site but i'm ideally after a system that I can just plug into the T.V , whether it be mini PC,laptop, old Wii ect that can just be used to play old school emulators like Colecovision,Atari,Spectrum,Amiga/ST/Mame ect ect using one Joystick/gamepad.
Does anyone have any recommendations on where to start, what hardware to use and best place for Emulators and Roms.

Thanks in advance for any help advice or directions on where I should be looking.

Shane