As far as specialty programs go, they're not all that important. Sure, they'll give more "exposure" than a school which lacks the program, but the ultimate goal (employment), will certainly not be linked directly with any school's specialty program.
You need to be specific with your goals. I understand you want to work in land-use law. I used to work for a small firm (as a law clerk) which specialized in land use law, so I have some idea about what they do, etc. With that being said, many different types of places practice land use.
You could work for the federal government; you could work for the county or state in some capacity; you could work at a big law firm which has a land use specialty; or you could work at a small law firm (amongst many other things!)... I hope you get my point.
Based upon those possible avenues of where and how you could practice land use law, you'd want to decide upon which type of school would best serve your purpose. For instance, if you wanted a big law firm and wanted to work in land use, then you'd want to go to the highest ranked school you could get into (of course that's an oversimplification).
However, and as you said you didn't want to accumulate much debt, you may want to consider lower ranked schools (which are still good) who offer you a scholarship. You mentioned your GPA (3.4) but not your LSAT. Have you taken the LSAT? This will largely determine which schools you could get into and which schools will offer you scholarships.
Lastly, keep in mind that, save for the top top schools, law schools are regional. So if you don't really want to uproot your whole life, you may want to consider a school that has pull in your region.
One more thing (i know said "lastly" above): I personally don't think you need extra certification for a land use specialty. Your experience will certainly appeal to anyone employing in the field. You'll have connections and you'll have credibility (how many 20-somethings can say that they've been aspiring to work in land use law?).