I second everything written by cosmopolitanita. I would add the following:
By "environmental law," have you thought through what exactly that means? You mention that employment prospects are important to you.
Bear in mind that, with but few exceptions, environmental lawyers at the large, prestigious firms make their livings by representing corporations that are the alleged "environmental offenders." In other words, when government agencies, environmental activist groups, or individual plaintiffs scrutinize (through the regulatory compliance process, real estate/zoning procedures, public relations, etc.) or attempt thwart (through litigation) the industrial activities of a corporation, such a corporation will turn to a biglaw firm with a well regarded environmental group (i.e., your best employment prospect).
A potential upside of pursuing environmental work (i.e., assuming you are able to land a summer associate position at a large firm in 2010 and start as an associate in 2011 - for which you'll need to be no worse than the top 2-3% at VT) is that it could be in very high demand for the next four (and possibly eight) years. "Potential," because it will all depend on the presidential election. Environmental groups at large firms expanded tremendously in the 90's, because of drastically increased environmental law enforcement under the Clinton administration. Since early 2001, however, not only has there been zero enforcement, but many of Clinton's (and Gore's) environmental policies have been suspended or done away with entirely. If a Democrat wins this November, you can expect to see a torrent of renewed environmental enforcement.
If by "environmental law" you mean to say that you want to "fight the good fight" on behalf of the environment, then just try to keep your law school debt to a minimum. You'll find that the crushing weight of law school debt drives many a would be "do-gooder" into biglaw (or, in the event they graduate $150k+ in debt without a biglaw job, into deep depression). Cost/debt aside, VT's environmental program would likely be beneficial in the event you choose this path (i.e., not working at the large firm/corporate level).
Lastly, a word regarding your comment that as "an archaeologist, my main interest is cultural relationships with the environment." I too had certain intellectual and academic interests (personally and from undergrad study) that I assumed I would be able to indulge in law school and as a lawyer. I hate to be the bearer of harsh tidings, but you need to disabuse yourself of any notion that law school will accommodate such interests. In your second or third year, you'll be able to take an environmental law class, but it will entail studying statutes and reading case law, just like most law school courses. Sure, you might also take some theory or policy oriented course to your liking (especially if you can take a grad school course outside of the law school at the university), but that's one out of nearly 30 courses. It's a relatively tiny minority of law students who get to indulge their intellectual and academic interests - while attending Harvard, Yale, Standford, Chicago, etc. - and even then, they too are attending a professional school. Once such students (who were on law review at such schools) finish their clerkships and land jobs as law professors, when they're not busy teaching first year courses, they'll publish articles in law reviews on topics such as "cultural relationships with the environment."