Without even considering material and insoles, what color? Before buying a really cool looking pair of camouflage patterned boots, think. Will these be instantly noticed by people on the street as out of place? Did you pack a pair of pants or are you wearing these with a business suit or skirt? I suggest any city walkers consider long and hard a pair of BLACK boots or shoes. A black boot under a pair of pants is a pair of black shoes. Black shoes are just shoes. They do not tell a story. They do not alert passersby to your weapons or cause them to look twice. Plain black is the urban camouflage.
As for types and kinds of shoes and what you need for the terrain you cover, I like this site for good information: http://www.rei.com/learn/expert-advice/hiking-boots.html. They have a video and good advice as well as an outlet for shopping.
This site is an informational write up on the subject. http://www.patc.us/hiking/gear/boots.html
So, in the bug out bag or on the outer side of it, you should have a good pair of shoes that are better than what you have to wear to work daily. These shoes should be slightly broken in by use. They should have several pairs of socks packed inside of them. Pick a pair or two for several seasons. Two pairs of socks for the summer and two pairs of winter socks should hold you in good prep!
If you are going to do any weather treatment for the boots before placing them with the BOB, do. NIKWAX offers a video on YOUTUBE.com on how to weather proof your boots. If your manufacturer recommends a brand of water sealant for your boots, buy that type and use it. If you don't know what to use....all leather boots can use beeswax to seal.
I can not in good conscience recommend a particular brand name of boot to buy. Price point is a point for me but not so much that I would trade wear or wear ability This is a survival item that should be on the top of the list and deserves the best investment. Buy the best you can afford then in time buy a second pair.