Hi, Justin.  Urban design is a great field, though sometimes ill-defined in terms of suitable educational prep-- as you've discovered already.  Some thoughts:

1.  There are multiple paths to UD practice, not a single correct way.
2.  Don't consider the PhD until much later, and only if you find yourself burning to do research and pursue an academic career.
3.  You're right that a dual-degree approach is the best path for a field that spans disciplines.
4.  Every degree program's focus and quality is different.  So, all things assumed equal, and considering you already have an architecture degree (the most important foundation an urban designer can begin with), I'd recommend combining planning and landscape architecture.  Other combo's could work fine, too, but from a purely disciplinary perspective, those two best complement your existing degree for a well-prepared path to UD practice.
5. Get as much experience and exposure as you can (even small bits) in planning and/or UD, starting now.  This means internships, exhibitions, lectures, reading... the usual.  You'll gain knowledge, personal contacts, talking points, and input on what about the field most interests you.

Good luck!

Thank you so much for the advice. I will look into a dual masters in LArch and MUP, which I was leaning towards because I feel like a MArch will just go back over the same topics I learned in my BS Arch. I feel that a LArch and MUP on top of my BS Arch will make me a more well rounded urban designer.

You're welcome.

Consider searching the forums here for threads on UD.  Beware, though, that the extent of diverging opinions can get daunting.  Still, there can be some good thoughts and comments.

from your post, it looks like your mind works a mile a minute, and just want everything everything. why dont you just get a dual degree in everything.

Ok, thanks for the clarification on a MArch. I just knew that most MArchs would go through structures, building science, and history again that I learned the basics about already. I feel that a MArch would only be helpful if I want to be a licensed architect as a urban designer. Which I have not decided on what profession I want to be to back up my career in urban design. I am leaning towards landscape architect and planner because it is different from my current education and has less licensing requirements then a architect. Does a architect who works as a urban designer have a edge over a landscape architect or urban planner who works as a urban designer?
 

Training (especially culminating in a degree) in architecture has two-fold benefits here.  First is (to state it very generally) an understanding of form, space, circulation, etc., and how to manipulate them.  Second is an understanding of common building types and their related functional and spatial needs.  This is important, since a lot of urban design work overlaps with master planning activities.

Landscape architecture brings similar tools, though at a different scale and using different forms as well as a better grasp of change over the long term.

Planning complements these two with sustained exposure to larger processes at work: the economics of both development and public finance; involvement by diverse stakeholder groups; formulation of public policy, including development standards and design guidelines; and politics in general, among other elements.

Again: this is a description of how different fields/ disciplines can work together for more complete urban design education and training.  Specific degree programs will vary considerably.

Hi!

I found this post really helpful because I am in a similar position as Justin. I want to do the same career path but instead of graduating with a BS Arch degree, I will be graduating with an Urban Studies degree. I was wondering if I should also do a duel masters in landscape arch and urban planning or if I should choose one of the other options that he listed above like arch and urban design for example. Thanks:)

Hi, what did you guys decide and finally opt for? A dual degree. In my country there are no such dual degree available. Is it best to take up urban designer and then work as Lp ar. for some years so that there's grip in both subjects? Will that be practical?

Go get a professional designation.. Planner / Landscape Architect / Architecture ... the title of urban designer has no significance, credibility or validation. Clients want to pay for legitimate services provided by professionals who can get a project approved and executed on site. Those with professional designations are essential to that process and contribute to the execution of real projects. 

Graduation is only the beginning. Why don't you work for a city in the planning department and THEN consult? Who died and made you God just because you graduated with a Bachelor of Science in Architecture (not even a professional degree)?