One thing is for sure: if Chris Christie runs it will be the end of Mitt Romney. Mitt has always been the moderate's choice in the race but the big man from Jersey would overtake him easily. Christie has some baggage (including a large waistline) but he'll be seen by a lot of moderates and some conservatives as a strong leader who can really challenge Obama in the general election.
I believe Christie would actually have an easier time winning the general election than the Republican nomination. If he wins the nomination he puts all the swing states in play (see previous posts) and even a few blue states. If he ran the table in the general election and won the swing states, Christie could end up with an Electoral College vote in the high 300s, easily capturing the Presidency.
This is all assuming he's running. I thought Mitch Daniels and Paul Ryan would run so I'm used to being wrong. Right now in Trenton Governor Christie and his team and considering how to put together a last minute strategy to get on the ballot in several states (like Florida) that have moved up their primaries. We should know by Friday if he's running. Many in the GOP are not at all satisfied with the current crop of candidates and a lot of pressure is being put on the Governor Christie to run. Simply put, the GOP doesn't want to lose an election to a President who is so obviously vulnerable and Chris Christie may be the answer they are looking for. While he may not be Ronald Reagan, he'll be able put together a coalition based on strong leadership that would be very hard to beat.