Guy Davis of Calgary has created BabyNameMap, an interesting Google Maps mashup of popular baby names from around the world. The map locates where this data exists in the world and lets you browse top boys and girls names.
In the US, his information is posted by state and includes graphs of popularity over a period of years for each name. At first I was skeptical, wanting to know where the information comes from. The source for the states I viewed was the Social Security Administration 2006 records. Pretty reliable as long as you're not hoping to get a check from them once your little ones are grown.
Another thing that threw me was the "Popular" and "Top Rated" boxes on either side of the mashup, but when I read that these are chosen by viewers who give 5 stars to names they like, I didn't pay attention to it anymore. While I was a little surprised to see that "William" was the most popular name in VA, NC, and SC. When I saw "Jose" as the #1 name in 2006 in Texas, and "Angel" in the top five for boys names for California, I relaxed. "This site must be accurate," I thought.
I tried out these names and found that for 2006 according to the Social Security Administration: Preston: (popular in SC-72st and common in GA-97th); Luke: (popular in SC-51st, NC-41st, and VA-43rd); Rachel: (popular in VA-33rd, NC-52nd, and SC-61st); Ruth: uncommon in USA (ranked 373rd)