In terms of the amount of learning involved and the amount of work needed to get a photo looking the way you want it, or at least, better than it came out of the camera, Elements is the hardest, then Lightroom, then Snapseed Desktop.
However, if you were to start with Lightroom and watch the training videos at Adobe TV to get a head start, you could then get Snapseed to use as a Lightroom Plugin as well as a standalone editor. And/or you could get other plugins that work with Lightroom that can give you one-click effects that are then adjustable. Notably good ones are Nik Color Efex, OnOne Perfect Effects, and Topaz Adjust.
I'm currently using Lightroom 4.3 with Elements 10, the entire Topaz bundle, Perfect Effects 4, and Snapseed Desktop, which all makes for fast and powerful photo editing. I use Lightroom for asset management (selecting, sorting, tagging, rating, etc), plus initial adjustments to tone and colour - which is sometimes all a photo needs. I use the rest as plugins to Lightroom which saves having to run a program, save the result, run another program, load the previous result, etc, etc.
So, all in all, I'd recommend Lightroom to start with as it will do most of what you'd want to do, then add in extra bits as you learn more.