Where can I find election results for 2004 (vote counts, percentages, demographics) as they compare to this year’s results?
Try here first: CNN.com Election 2004 - U.S. President
There is a lot of detail but sometimes you have to try several different ways to get the data as some of the links are broken.
electoral-vote.com still has its 2004 post-election results available: Electoral Vote Predictor: Nov 8, 2004. If you hover your cursor over the individual states, it shows the results in each state.
US Election Atlas is a fantastic site for election results, from 1789 to present. Check out the ‘Election Results’ tab at the top of the page.
Daily Kos is another good one with an interactive map on Pres, Senate, House, and Govs races for the last 3 cycles.