I am in Ames (30 miles north), but there are some nice neighborhoods to consider in DM. I used to work in the Owls Head neighborhood on 28th close to Grand. The houses in that area are quite expensive and historic, but the houses north of Grand and Ingersoll were nice and there is a range. Also, the houses south of 235 around 42nd are really nice area- close to the DM Art Center. Ingersoll has lots of shops around 28th-35th St. area.
Otherwise, West Des Moines has some really neat homes in the Valley Junction area. I think within walking distance to 6th or 8th would be nice. WDM also has a lot of suburban sprawl outside of the VJ. Urbandale, Johnston, and Ankeny have a lot newer building occurring (Mcmansions, people hutches, and sprawl), but like another poster pointed out that there are also older neighborhoods in these communities that are quite established.
Some of the areas around Drake University are kind of rough and others have potential, and I think the S.E. side and some in the East may be kind of rough as well- not sure, but the couple of times I have been there they were not so nice. On the other hand, the East Village just experienced a revitalization and has great restaurants and galleries- not sure about housing.