I live in Wilchester south of Memorial. Some houses did flood, but it was mostly due to improper drainage on their property.
There are actually very few "Wilchester" houses for sale of any quality. Most either back up to Memorial, are on or near the Long Point fault line, or in poor condition. A 3,000 SF house that has been updated (kitchen, bath, floors, etc.) will typically sell for $180 - $200 PSF. During the housing run up in 2006 & 2007, the best houses were selling for over $200 PSF in less than a week or never even hitting the market.
Wilchester Elem. is being rebuilt on its current site, so the kids will be in temp buildings for 2 years. The city rebuilt Walnut Bend & Briargrove Elem. on their current sites and it took around 18 months in each instance.
Suprisingly, Lakeside Country Club and the bayou provide a buffer from the elements located south toward Briar Forest. The intersection of BF & Wilcrest is pretty rough. I haven't experienced an increase in crime in the 5 years I have lived there.
Bottom line: The neighborhoods zoned to Wilchester & Rummel Creek Elem (along with Memorial Middle School) have historically held their value since they were constructed in the mid 1960's. Every home that sells is purchased by a family, no empty nesters or young couples. It makes for a great environment to raise a family. My home has appreciated significantly in the 5 years I've owned. I don't think you can go wrong.