The Mac Mini has a DVI port on the back. You can connect any DVI display to it. If you use the DVI -> VGA adaptor you can connect any VGA display to it too. That should cover most of the available displays, just not the Apple 27" one.
I bought a 24" AOC LED display a while back for a customer. It was very thin, looks nicer than most in terms of the casing and design, had lots of connectivity and produced a decent enough image for the price. It was good value all round unless you are very particular about colour reproduction, which I'm guessing you won't be in this case.