I'm about due for a positive post so let's visit the corner of 14th and Pine on Capitol Hill, specifically the building on the southwest corner.
I think it's fair to call this the apotheosis of functional diversity; on the ground level it houses an Italian restaurant, a furniture store, an architecture firm, a salon, a children's clothing store and a gardening store, all of which are capped by what I assume are apartments. Spatially this building is not overwhelming; it takes up about a sixth of the block on which it sits (as opposed to the Braeburn Apartments, which take up half of an identical block and are a story taller at the corner, and, thankfully, house the Online Coffee Company). Economically, I would say the retailers in this building are reasonably priced though not exactly appealing to a different "class" of consumer (they are all independent outlets, to my knowledge).
Take a step back and you'll notice that the entire corner is diverse. I took this photo from in front of Online, across the street from a caterer to the west and a church to the south. Not to mention that there is also a fire station, a watch shop, a piano studio, a real estate office and the sales office for the mythological Cameo Condos (more on this later) on the same block.
Granted, this corner isn't bustling with activity throughout the day. I think that is due to the fact that it is bounded on two sides by primarily residential areas and by a major road (Madison) a block away to the south. Regardless, this type of building -- modestly sized and functionally diverse -- seems like a better building block for the neighborhood than, say, the Press Condos, which take up an entire block of Belmont north of Pine and only offer the community a snooty restaurant/bar with a misspelled name that I can't even bring myself to type...oops, there is that negativity again.