First, you don't have to study architecture first.

True, most of the more prestigious MUP programs have a prereq for a 5-year architecture or landscape architecture degree, or a masters of architecture, landscape architecture, urban policy or the like.  But there are other MUP programs with few or no prerequisites other than a bachelor degree in anything.

Also, there are a number of dual M.Arch/MUP programs, so studying architecture and urban planning simultaneously would be another option.

As far as the academic experience goes, most M.Arch programs have a more artistic focus than most MUP programs.  After that it depends what sort of career path you take.  The more artsy of the urban planners tend to end up in joint architecture/planning firms - in which case it doesn't always matter that much which background you came from. I know lots of architects who have gotten their certified planner credential after working in one of those firms for awhile - it doesn't require a planning degree, and there are only three states that currently license planners.  And a lot of MUPs end up in not so artistic roles, working for municipal planning departments, town planning and zoning offices, that sort of thing. 

Thanks for the input. So your saying if I want a more artistic planning/design career it would be best to just stick with architecture and don't bother with an MUP? Because I was planning on getting a BS in architecture and then doing an MUP.

Well I'm not saying that any one route is the best one.  I just wanted you to know that there are options.

The planners I know who have more artistic roles are the ones who work in combined architecture/planning firms, or landscape architecture/planning, or who work for non-profits in various capacities.  The ones who have municipal jobs don't seem to have very many opportunities for creativity.

If there's any chance that you want to be an architect, definitely go with a professional degree (NAAB-accredited B.Arch or M.Arch.).  There are thousands of threads on here about the frustrations and limitations of becoming a licensed architect without an accredited degree.  While it's possible in some states, it's certainly an easier, usually shorter, and more flexible route to do it with the accredited degree.   But licensing isn't usually an issue for planners.  AICP certification is important to many employers, but you don't necessarily need an MUP for that. 

You could also finish your bachelor degree in just about anything - maybe something more artistic - and then get the dual M.Arch/MUP.  To go that route you'd just want to make sure that you got in the most common pre-reqs as an undegrad: a semester or two of architecture history; calculus; physics; some freehand drawing.

I'm really just weighing my options and this puts things into perspective, but thanks again for the input! 

There's a difference between urban design and urban planning.

Very simply put, urban design is architecture oriented, and urban planning is more about policy making (of course, both fields deal with design and policy in the end). in school at least, I personally found urban design being more about addressing the economic/social/cultural/political (and what not) aspects of a city through built forms, spatial qualities, and program of a building or a city. Urban planning oftentimes may not end up with physical form--it's like developing a successful business model for a city. 

If you think you are so design-oriented, urban design would be a better fit for you, and in order to do that an urban design degree is an option, while an architecture degree being a must. If you're thinking of going to gradschool for UP, I would say pick your school carefully, because the importance of design in the planning field is weighed very differently at different schools. Try taking a lot of urban-scale design studios during your undergrad studies, and see how you feel about it. After all, in urban design, you don't get to design each and every building, which is a part of architecture you might find difficult to let go. Do keep in mind that both in UD and UP, practical issues eventually kick in, and it will be very difficult to fully stay an artist dealing with urban environments (being an artist and an architect at the same time makes more sense).

There is absolutely nothing artistic in an MUP course. Think CAD and GIS monkeys with tons of boring lectures. Urban Design, on the other hand could have some artistic components, but you will need an architecture degree for that.

Thanks everyone. 

Urban design, not urban planning, is definitely where I want to be. Just wondering what is the best course of action to get their while keeping my artistry in tact. 

Like getting a BFA then doing an MArch, or doing a BArch and then doing a masters in UD.

BArch and a masters in UD would be nice. Nicer if you take 2-3 years to work between degrees. I went to gradschool right after my undergrad for personal reasons, but wish I would have known things I learned in the field when I was in gradschool.