My husband and I relocated in a suburb just east of downtown Nashville (still Davidson County) in 2005. We moved here from a Maryland suburb 30 miles north of Washington, DC. Having lived "up North" most of my life, I am a serious Nashville convert! Cost of real estate is SO much more affordable, property taxes are much lower, and the people are just plain nice. OK - traffic can be a pain at times, but if you live in a major metropolitan area anywhere, there are ALWAYS traffic issues - goes with the territory. As for crime, like most places, it depends where you live. There are good areas and "bad" areas. You have to do your research. Salaries are lower than in the DC area, but overall, they are in line with the cost of living here.
Guess the biggest negative is that the state sales tax is 9.25%. OUCH! But, on the positive side, there is NO state income tax.
Bottom line - we are VERY pleased with our move here, and I don't see any reason to leave. We purchased a wonderful single family brick home for $134K that would have cost us easily $300K or more in the DC metro area. Taxes on it are less than they were for our 850 SF condominium. Winters are mild (compared with up North) - altho this summer ('07) has been incredibly hot and dry.
Come visit - you really might love what you see!