I'm setting up my MiSTer FPGA and want to prioritize a bit. I currently have DOS and Win 95 running, but plan to setup Macintosh and any other worthwhile computer platforms. Any computer platform welcome (I already have the consoles figured out). What are your "must try" game suggestions?

Edit: I just got back to this post and am pleasantly surprised by the response. I'll probably be adding most if not all of these to test since I have the space. Thank you to everyone who commented.