2:35 p.m. on October 1, 2009 (EDT)
Over the years, I have used tent and hiking poles of a variety of materials - steel, aluminum, fiberglass, wood, carbon fiber, bamboo. Wood for hiking poles and staves is great, since you can carve it into various personalized and fanciful shapes and you can put those "I've been there" medallions on them, plus wood works well for making "camp furniture" (tripods for holding the wash basin and shaving mirror, seats, holding pots and whole birds above the fire for cooking, etc). In some parts of the world, wood is available for tentpoles, saving the weight of carrying them (OTOH, the tents you would use them for are pretty heavy themselves).
But as fun (and retro) as wood is, other materials are better for the "modern" hiker (WHAT?!?! the Old GreyBearded One "modern"? GASP! CHOKE! COUGH!)
Steel is too heavy for tent poles except for car camping, so forget that.
Fiberglass looks good at first glance. However, having broken fiberglass tent and ski poles and experienced at first hand the extreme difficulty of making a reasonable field repair, I strongly recommend avoiding fiberglass for either application. The resins used for fiberglass also age poorly with exposure to UV, meaning they deteriorate fairly rapidly at high altitude.
Bamboo ski poles are strong and light. But when they do break (and they do weaken with age), they have the same repair problem as fiberglass - not a clean break, but a fibrous one that seems to keep growing beyond the clever splints you put on them.
Aluminum, especially the modern alloys, has proven excellent for tent poles in my experience, and for ski and hiking poles, especially adjustable ones. Although I have bent tent and ski poles, I have never actually broken one of the high quality ones (I did break a pole I got for $2/pair from an end-of-season ski rental place's sale - while using it as a pole for towing a gear sled, which I admit was rather abusive). Bending a section of an adjustable ski pole even slightly means the adjustment goes away. If you are very careful (and experienced at bending conduit and other aluminum and steel tubing and pipes), you can straighten aluminum poles. As I noted above, I have had excellent experience with Easton aluminum tubing in tent poles and ski poles.
I have not used carbon fiber tent poles except in loaner tents. But I have used it extensively in hiking and ski poles and camera tripods, as well as bicycle frames (I used to race bikes at a National level). Over the past 20 years, carbon fiber in such applications has come a long way. The older versions suffered from some of the same problems as fiberglass - UV deterioration of the resins, fibrous breaks that were difficult at best to splint, especially in the field, and so on. OTOH, I have never broken a CF pole or bike frame, despite extensive use, including some that was pretty abusive (ever do gelandesprungs when running down trails?). The only CF bike frames I have seen broken were in severe falls during races. Similarly with broken CF ski poles.
All that said, I prefer to stick with aluminum tent poles (Easton) and carbon fiber bike frames and hiking/ski poles (adjustable).