Apple Aperture & Presets (effects)
In the Adjustment Pane in Aperture, a number of effects are built. But cruising around on the Internet, one hears of many, many more preset adjustments. Some at a low cost, and others for free.
I've already got the NIK plugin suite, so some of the more routine adjustments are at my fingertips.
What value is their in accumulating plugins? Some of the enhancements for portraits look intriguing, and I don't think I could match them. Not at my current skill level.