Oooh boy, do I agree with this recommendation! Tall boots never fail. You can wear them with a slim maxi skirt, or tuck jeans or leggings into them---they don't just make a look, they ARE the look.
Which means that I have to be really picky about the boots I buy. Everyone notices the boots you're wearing, so the heels can't be too high, or too low; they can't be too pointy or rounded, and you can't have too many buckles or straps on them because instead of just wearing "boots", you're wearing those-pointy-boots-with-all-those-buckles. And everyone in the office remembers you wore them last Tuesday. Anyway, I guess the word I'm looking for is...neutral. If your budget and closet allows, you can go crazy with low, high and over the knee boots. But for closet basics, I'd get just two: a black one and a cognac or caramel colored pair with a two inch heel.