I know this was talked about last week but the lefties really didn't have the guts to come up with a definition other than Obama's. So here is a reputable source and their definitions.
http://www.reuters.com/article/2010/...68D3QD20100914
For the comprehension and reading impaired; this article describes the middle class financially (one determining factor) as a household having an income between $25,000 and $100,000. This is affected by location.
This section is more about social class and it is interactive. I thought it was fun and interesting.
http://www.nytimes.com/pages/national/class/index.html