I use pecan, oak, and apple since those are the most commonly-available hardwoods around here. Where I used to live, I could get cherry, plum, apricot, alder, hickory, etc. So I've been using lots of different woods throughout the years and used to accept the conventional wisdom that different woods were better matched to different meats. You know, after all this time I've come to the conclusion that most people, including myself, can't really taste the difference. Often, the perceived "strength" of the smoke flavor has more to do with the how well the wood is seasoned and - this I have found to be the very most important factor - how expertly the fire is managed. I did a blind taste of salmon using alder and oak and no one could tell the difference. Yes, some woods like mesquite can definitely add an acrid flavor, and cherry can give chicken and fish a darker coloring. I just use whatever is available and well-seasoned.