Personally, I'd go with EnderIO Sterling Generators, they're fairly smart, and the EnderIO Power Monitor allows you some fairly fine tuned control over when the generators kick on so you don't waste power.
Depending on the mod list you are using, my preferred wood -> power chain usually runs like this.
Harvest the wood somehow. I usually use either MFR or a Thaumcraft golem setup depending on how deep into RF I've gotten. The advantage to Thaumcraft is that it keeps working even if the power goes out, but you don't get the added benefit from having sludge to boil into miscellaneous junk (that could either be a plus or minus to using MFR). Also, if I'm playing with Rotarycraft installed, I usually set up a second MFR harvester that only covers a small section of my tree farm and set it to sheer leaves, that way I can also feed an RC ethanol system as well.
Then I pipe the wood into an ungodly number of Railcraft coke ovens. Again, the benefit is that the coke ovens don't require any external power or fuel to run, so even if my base has a completely blackout, the system will still run. The other advantage is that I get the creosote oil out, and that provides a small bonus of power.
I then run the charcoal into an automatic Thaumcraft Alumentum production system. All I need to add is some Perditio (usually from a cobble generator), and it gives a pretty significant boost in power output compared to just burning the charcoal. Also, side tip, if you are running GregTech 5, the tiny piles of ash you get from the blast furnaces are great sources of Perditio, at least to supplement the cobblestone, and it gives you something to do with all that ash you get from the bronze-plated blast furnaces. You get more Perditio from the tiny piles, rather than combining into either small or normal piles (each tiny pile is 1 Perditio, each normal pile is 2).
From there, I usually run a max size Railcraft low-pressure boiler off of the Alumentum, and a smaller LP boiler off of the creosote oil. In my series with Gregtech, I'm running my GT power off of the solid fuel boiler, and my RF power off of the creosote boiler. The downside to the entire system is that it takes a metric crapload of coke ovens to produce a decent amount of creosote, but coke ovens are just clay and sand, and it's basically free power. You could also easily use the same system substituting the coke ovens for any sort of furnace. Personally, I like to not use power as part of my primary power generation system, at least until I'm looking at refining oil.
Mods required for the full setup:
MFR / Thaumcraft
Thaumcraft
Railcraft
If you want to squeeze even more efficiency out of the system, you can also pipe the extra saplings into a forestry ethanol production system, or an IC2 biofuel cell production line. I haven't done that myself (yet), so I can't tell you how many you could easily run.
