For starters, though, my advice is to get into this gradually and figure out what you really need, rather than laying out a pile of dough right off the bat. First, get some good, all-purpose leather boots that are crampon-compatible. My first choice likely would be Montrail's always reliable Moraine AT ($230). Other excellent choices include Scarpa's Super Manta M4 ($239), La Sportiva's Makalu ($245), and Boreal's Asan ($255). These will likely take you anywhere you want to go for the next year or so, whether it's extended backpacking, cramponed glacier travel, or low class-5 rock. With good technique, they'll even manage on pretty steep ice.
Meanwhile, find a mountaineering store in....Lincoln (sound of barely suppressed laughter), or wherever your travels lead you, and rent some plastic boots. Get a sense of how much boot you need. Then you'll be better prepared to buy a decent all-around plastic such as the Koflach Degre ($239). Or, you might find that a mid-weight plastic boot such as Scarpa's excellent Inverno ($300), which can handle pretty technical ice with the right crampons, suits you fine. You can step up to a full-on technical ice boot like the Asolo Ottomilla ($399), but I think it will be some time before you could take full advantage of it, and I don't mean that as an insult. Bottom line, you can spend less than $600 and have two pairs of boots that will suit 90 percent of the terrain you're apt to encounter any time soon.