It's impossible for Republicans to get a majority in 2010. Keep in mind that in the Senate they are 20 seats behind and, in the House, the margin is even greater at 258-177.
Now, there's no doubt that Democrats will lose some seats (I would only put Arkansas, Colorado, Illinois, Nevada, and North Dakota in the tossup category) but even if they won every single one of those, that would still leave them at 45 to Democrats' 55 majority.
And Democrats have yet to deploy their secret weapon: A jobs bill, which will undoubtedly help them greatly in the midterm elections. Senator Durbin is working on it as we speak, and after health care is taken care of (knock on wood) that would probably be the next item on their agenda.
PS: Nice to have you back.