Barry
If you are going to buy a ladder, a couple things to consider:
1) If the ladder is too heavy to get off the truck, you might end up spiking stuff you don't need to. I have found alum. ladders to be lighter generally than fiberglass. Keep 'em away from lines, though.
2) Check the weight rating. I can get away with using a flimsy 20' alum. with a 200 lb. rating to get in most trees because I only weigh 145. My boss is 230, and my lil ladder scares the heck outta him. He also has a 28' fiberglass, but it takes 2 guys or one strong guy to get it off the truck. I rarely use it because it is such a pain to handle.
3) Make sure you have a place on the truck for it. If it can't ride with you every day, it won't be much help. A 24' ladder won't fit in an 11' ladder box on the chip truck.