I've only had one set of trekking poles. An aluminum BD set that have been pretty good to me. I bought them several years ago, and sadly lost one last summer while on my way down a traffic jam on the cables at Half Dome. I bought a carbon cork BD pole so that I'd have two, and I really liked it too. But I lost it on a cross country jaunt through the west fork of Bear Creek a couple of weeks ago.
I'm just going to buy a new pair of poles. Any of you guys have a preference on aluminum versus carbon?