I really like this Matt Yglesias post in which he points out that George W. Bush's success with Congress is mostly a myth believed in by liberals. I'd add a couple of things. One is that the Republican House under Tom DeLay was, by all accounts, highly efficient in passing things that DeLay wanted to pass, which was an asset to Bush that he didn't earn...as long as he was doing things that DeLay wanted.
The second thing is that Yglesias accounts for some different outcomes by referring to differences in party discipline in the out-party: Bush was able to get cooperation from Ted Kennedy and Max Baucus, while Obama has thoroughly failed to get cooperation from Republicans; to the extent he succeeded, it was by compromising proposals to secure votes of the moderate fringe (Snowe, Collins, Brown), not by getting the active support of any mainstream Republicans.
I think that's true, but I don't especially think that it's interesting to think about why that is. I think the story that best explains it is about one perhaps asymmetry between the parties: Democrats are simply far more interested in policy, certainly in domestic policy (not the economy, but the rest of domestic policy), than are most Republicans. Ted Kennedy and George Miller were willing to cut a deal with George W. Bush because they were really, really interested in education. What, exactly, is Chuck Grassley really, really, interested in? I have no idea. Jon Kyl? No idea. I don't think there's a gap on foreign policy, at any rate not traditionally, there are some Republicans who have a strong domestic agenda, but I do believe there's a fairly big gap between the parties on it.
Of course, Republicans do care a lot about certain tax cuts, and Barack Obama was able to use that to cut a deal on taxes late last year. But what's the GOP agenda on health care? Education? Climate? There just isn't much of one -- either Republicans don't believe those things are problems, or they don't think that government can do anything. That's certainly a legitimate position (don't like it? Elect the other party!). But it makes it a lot easier for Republicans to maintain party discipline, and a lot harder for Obama or any Democratic president to cut deals.