If you're going to invest in a versatile pair of boots then you should probably look into a great pair of Chelseas. The boots are perfect in both casual and dressy situations and its signature elastic gores make it great for travel too. One pair you'll want to take note of is this Chelsea Boot from Beckett Simonon, which features handcrafted uppers made from Argentinian leather and is built on a flexible Blake construction. 

$165, beckettsimonon.com