There’s a great site, called "Opensecrets.org", that details which candidate receives how much from whom. Interestingly, though most of the top 20 contributing industries are substantially the same, it doesn’t appear that the Oil & Gas industry is in the to 20 for the Democrats, as it is for Mcain.
Here’s a breakdown of what Obama has received so far by industry:
Here’s a breakdown of what Clinton has received so far by industry (not terribly different from what Obama is getting):
And, finally, the Mahatma Gandhi of the Far Right, John McCain: