Hispanics, southerners, and people with family ties to New York.
Having looked at the data, Bush improved best in the upper south, Arizona and tri-state area (NY/NJ/CT) so you are right.
Bush also improved a few points in Texas, California, Florida and Illinois. All big states that helped with the national popular vote margin.
Looking at the swing states, he only gained a point or two. But this was cancelled out by Kerry eating up the Nader vote. So Kerry kept WI/MI/PA/MN with similar margins.
Something interesting, Kerry did much better than Gore in the Mountain West. That can be explained with Nader doing quite well in 2000. Nader won 5% in Montana and 10% in Alaska! Kerry was able to do much better than Gore in states like MT/AK/ID/SD but still lost these states. I think these states are more secular so the gay marriage refrendums wouldn't have flipped too many voters unlike the south. Might also explain why the Obama 2008 campaign thought they were slightly winnable.