those look like soil millipedes. They do eat decaying plant matter in the soil. If you have small seedlings you might want to keep them away to prevent accidental feeding from them. Think of them as composting worms with a lot more legs

Ajuga reptans aka bugle. Yours might be the named variety Burgundy Glow judging by the leaf colour. Much hated by some posters on these forums but I like it and it is a very useful plant for damp shade. A British native.

See what I mean about conflicting reports on how beneficial these can be? My compost pile has definitely been untended. I saw the grubs when I first turned it after a winter of leaving it alone. Here a post saying that the grubs are beneficial: http://faq.gardenweb.com/faq/lists/soil/2002013027009234.html Here's another one on the exact same grub, saying that they can be very destructive to your lawn: http://en.wikipedia.org/wiki/Green_fruit_beetle And Soldier fly larva are pretty much acclaimed for being helpful, so we should be careful lumping everything into a single category. http://extension.oregonstate.edu/news/story.php?S_No=802&storyType=garde I was hoping for a solid ID on what kind of grubs I had in my compost, but my pictures may be too fuzzy for anyone to tell for sure. Here is a link that might be useful: Soldier Fly Larvae

Try this link to the University of Florida insect resources. At the bottom of the page are resources from other sites that UF recommends. Here is a link that might be useful: Insect Pests