What kind of boots did you previously try? You might be suprised with some of the newer "tactical" boots (the funky hybrid looking ones). Many offer the comfort of running shoes, but provide good ankle support, and keep debris out of your footwear. Altama, Bates, Blauer 5.11, and Converse are a few companies making these style of boots. Heck, even some of the cheapies are decent. Some even feature a side zipper, makes gettin' them off when you're tired a lot easier. Gore-tex lined boots are awesome if you ever encounter snow or water in the field. I've seen many of these boots going from $40-$100. I'd consider that very reasonable for one of the most important pieces of gear. My boots have saved my ankles many, many times. I am kind of a clumsy oaf though. But heck, that's just my 2 cents. Really the best method is go with what's comfortable. Ultimately, experience is the best teacher.
***Many apologies for the off topic post, that is, the utter lack of showing off sexy gear. I figure discussing it might be excusable.***