As long as there are different races, race will be an issue to some. For example, in many Latin American nations there has been so much mixing that some (less informed) people treat the nationality as a race, and yet, there are still issues of the majority verses those that are of more pure Spanish blood. It certainly isn't an issue to everyone, but with immigration issues and the war on terrorism, issues of race come up. Things are better than they used to be and many are open-minded today, but there are always a few that aren't.
Race is critical to understanding the composition and mindset of the US culture. Every race has its own issues, beliefs, convictions, and morals. Because each race is different, it is important to understand and honor the things that make us different. This allows for a greater understanding and a greater tolerance which leads to a greater nation.
If by important you mean still a problem, then yes race is still important. There are parts of society that are melding together and race is become very gray because people have to identify as various different things. I think this problem will go away the more common this becomes.
There are certain members of the population that somehow think racism is over because there is a black President. In truth, racism is probably more open and overt than it has been in decades. Given the growing numbers of minority populations, race is actually an increasingly relevant factor in the nation.