Bruno Ferreira wrote a good article on how to improve the PC as a gaming platform. As someone who is a PC gamer, I couldn’t agree more with what he says. It’s extremely difficult to build a system for PC gaming, and very difficult to buy games since the metrics used are so difficult to work with.
In my opinion once every 12-18 months the platform should create a new standard based on the latest and greatest. It’s assigned a number, likely the year. A software profiler would then establish what standard your computer meets. Don’t buy any game that exceeds that number. A game can support “minimum” and “optimal” but would just put the number below vs. spelling out all the specs. Profiler could then advise on how to upgrade. For example if you upgrade you’re weak GPU and add more RAM you’d meet the requirements for 2013. Or just leave it at 2012 standards if that’s good enough for your needs.