Denver has a variety of neighborhoods that might fit your needs. The first question for you to determine is "how much do I want to spend?" Of course that is difficult to do because you don't know exactly what your money can buy. When working with clients I usually prefer to start in a lower range and work up. Looking at an $800k home, then comparing it to a $400k home really isn't fair!
If money is no object, look at homes in Hilltop around Cranmar Park. This area is rich in architectural styles, so much in fact there is a walking tour book written specifically about it.
The Country Club area also has many historic homes and estates worth looking into. I personally love the wide tree lined streets of these Denver neighborhoods.
Another very fine area is Bonnie Brae, named after a Scottish town, this neighborhood is the only one in all of Denver where the streets curve. It is located just south of Polo Grounds and Cherry Creek.
If you are wanting to stay on the lower end of an urban budget, look at homes in NW Denver (neighborhoods of Denver Highlands, Sloan's Lake, Sunnyside, etc.) This area was once the blue collar neighborhood where homes are diverse as the people who live there. Victorian, 2-story Denver Squares, solid brick Crafsman homes line the streets. The wonderful urban village at 32nd and Lowell has the original Heidi's Brooklyn Deli, so maybe you can capture a nostalgic taste from NYC!
Since you are an Urban Planner, I would be remiss if I did not direct you to our two urban planner's dream neighborhoods of Stapleton and Lowry. These areas are urban infill built on the former airport and Air Force Base in the city. The villages located here are wonderful. Lowry is a National Historic District with a variety of housing.
Stapleton is being built by Forest City, it boasts the best of 22 builders presenting homes in all price ranges. There are row homes, townhomes, condos, single family of many styles and even an area that looks like the East Coast Shore (sorry no ocean).
My favorite part of both these urban villages are the wonderful shops nearby. There is also a huge mall at Northfield.
I could go on an on about Denver neighborhoods....hope this helped!