Well.... like most folks here I could fill up two or three BOB's with nothing but my blades, and still have to go back for a second trip...

But I think the original posted was thinking on person blade, not in a gear bag or BOB/GHE/EDC bag.
The original poster had a picture of a Smith and Wesson Extreme series blade, which I do not really care for. My thoughts on Urban Survival tend to be more escape and evade then anything else. I love my HEST as a EDC blade, same with the RAT Izula. But my Urban Survival gear is simply a Kershaw folder and a Letherman Surge or Core. It you are wearing them in most environments they aren't going to draw a lot of attention, but they do cover almost all the basis for needed blade/tools. Sure they aren't "tacti-cool" but they will (IMHO) get the job done better then a lot of the stuff out there. I would love to carry a small fixed blade but it really does attract too much unwanted attention in todays city environment.
Please keep in mind that your blade/multitool is only one part of your Survival Kit (Urban or otherwise). Your clothing, boots/shoes, and whatever is on your person are just as important. Having the very best in Multitools, and a huge survival blade does you little good if you have sneakers on, and have to climb over tons of rumble in 20 degree weather in a tee shirt. The likelihood that you are going to need to fend off Zombie's with a RC-5 are pretty remote, but the fact that you might have to walk a long way to get clear of the danger zone is very likely. Don't count on your EDC bag. Dress as thou you are going to have travel a distance in what is on your body, and nothing more. Little things can make a huge difference. Example, I carry a pair of good safty glasses in my jacket pocket all the time. I always wear fairly heavy, quality slacks WITH a good quality leather belt. I wear solid hikers everyday.
So for Urban environment my blade choices are:
Leatherman Core or Leatherman Surge or SOG Power Lock or Victorinox Spirit
Kershaw Chive or Kershaw Mini Cyclone or KaBar Dozier OR Victorinox Fireman (Etc)
RAT Izula or RAT HEST or Gossman PSK
But as others have said, and I will repeat, you MUST build your gear around what works in YOUR Urban area, around your environment. Katrina, Haiti, 9/11, and any number of other examples out there give you a good insight into what you should have in order to make it clear of the effected area.