Building an "active soil microbe herd"
I was reading a discussion of fertilization on the Tomato forum, and DigDirt discussed how an "active soil microbial herd" is needed to break down compost, etc. I built a raised bed veggie garden last year by smothering the grass on my lawn and then filling it with a truckload of bulk "planting mix" from my local nursery. The mix contained mostly small wood fragments, compost, sand, etc. Things grew relatively well last year (as far as this first time gardener could tell) and I'm planning to amend the soil this spring with my own homemade compost, which is almost ready.
So my question is, would it be beneficial for me to buy one of the "soil microbe starter kits" being sold at my local nursery, or is that just a waste of money at this point? I transplanted some potted plants into the garden last year, but I don't know how much microbial activity is going on in my soil.
What else can I do to ensure a healthy soil microbial community?