I used to detest a two party system, and in some ways I still do, but someone made a point about multi-party politics once that made a lot of sense to me. What if some lunatic fringe group (i.e. Tea Party) actually drummed up 34% of the vote in an election where the Repubs. and Dems. were at 33%? Well, you'd get lunatic chaos.
I guess my main thing is that I like gridlock. I don't want one party running amok. I only want them getting together and only passing the really important stuff that means something tangible.
I realize that doesn't always happen, and this is a simplistic way of looking at things, but there's a reason that the stock market performs best when there's a Democrat in the Oval Office and Republicans owing Congress.