A lot of you are way more knowledgeable than I when it comes to dialing in effects, but for those of you who aren't wizards (and haven't moved on to higher end racks), I found this guide, and it is helping me understand my HD500x a lot more.
Line 6 PodHD Effects Guide
I used to use this when I had my PodHD actually. Very useful stuff.
MeAmBobbo is a great dude though. He's moved onto the Kemper now and is very active on the Kemper forums. He's made some of the most amazing advanced reverb presets for the Kemper and I strongly encourage anybody who has one, to try some of his stuff. I find that nearly all of the profiles that he has released/modified are some of the best ones around. Definitely the main profiles I use on my Kemper.