It's time to abandon PhotoShop

Every since Adobe came out with LightRoom, I have using it and it along with DxO. These have now become my main photo cataloging and photo optimizing tools. I find that I want to use PhotoShop about once every month or so. As a result, I have held off paying Adobe's high upgrade prices for PS and reduced my upgrade cycle to every other version. Since CS4 is getting a little behind now, I need to think about what I'm going to do.

Now that Adobe has decided to go to the monthly rental fee and eliminated upgrades, I am reluctant to part with that much money for occasional use.

My computers are all APPLE and running the latest OS X 10.8. Can anyone recommend an alternate more economical editor that will do layers and "near PS" capabilities?