I started off with Survivalist Generators for really early power. I added some RF Windmills for some more free power once I had some resources to play with. After that, I built an Advanced Generators setup fed by my tree farm. Saplings and apples go into a Mekanism grinder to create bio-fuel. Wood goes into a sawmill to generate planks and sawdust. Sawdust, planks, and bio-fuel all go into a Syngas Producer and the Syngas goes into a Gas Turbine generator. So far, that's covered most of my energy needs.
I am starting on the infrastructure for a Mekanism Fusion plant though, since that looks pretty cool. I'm sure I'll find something to do with all that power eventually.