Historically, the party that wins the Presidential election loses seats in the House of Representatives during the next midterm election. Since our founding, there have been only a few exceptions (1902, 1934, 1998, and 2002).
So the Democrats already have a very tough battle ahead as it is. I don't think they are looking to make it tougher at the moment. Pelosi's reaction to Holder's statement and the fact that the Senate Majority Leader opposes the ban are going to make it very difficult to pass any legislation right now.
We will definitely see such a bill introduced; but I do not expect it to gain traction until at least after the 2002 mid-terms. The Democrats demonstrated that they would rather try for the brass ring than immediate gun control when they stifled several AWB attempts after taking control in 2006. They have some significant opportunities now to establish long-running control over all three branches of government. I think they will not risk that opportunity in the next two years. Not to mention that the logical place to kick off a gun control fight would not be the AWB; but background checks for private sales.