Mainly I just pick up stuff I want to play or did play at some point in my life and wish I had available to me again. I only ever had the desire to complete one console set which was the US Dreamcast but now that that's done it is really just subsets that I think would be fun to have (Working Designs Sega set, 1998 US Retail Saturn set, etc...). Shooters, Fighters, Platformers, Beat'em Ups, and other Arcade style games especially are great for quick bursts of enjoyment at a time in my life when free time is in short supply.