Of course they did. Obama won California with 61% of the vote while McCain won Texas with 55%. But there are differences in the two states based on incomes. In California, 72.33% of the people with incomes under $30,000 voted for Obama and it was 57.56 for people with incomes over $150,000. In Texas, 63.29% of the people with incomes under $30,000 voted for Obama and it was 28.6% for people with incomes over $150,000.
So the difference between high and low income voters in California is pretty small, just 14.77 percentage points. But in Texas it is 34.69. Why would the differences between rich and poor be so much greater in one state? Maybe this is all affected by cost of living differences, but my guess is that its slight.
There was on an article on a similar issue recently in the Chronicle of Higher Education about the 2004 election. They found something similar. The data I used here comes from exit polls. To get to exit polls, go to CNN Election Center. You can click on a state on the map and then click on the link that takes you to the exit polls.