Well, as a religious man, I dare not use anything other than maple!
Divided By James, I'm going to go with Western Maple then, trouble is, I think around here, it must be pretty scarce. I've worked with the local "rock maple" before, and cracked some drill bits!
Vadim, your point has actually been lurking in the back of my head for weeks! I just didn't want to acknowledge it!... I guess, if I don't just go with a maple cap, then I will have to look into some sort of shimmy like DBJ said... argh!