To me, the most interesting part of the race for 2008 is the Reeps do NOT have a pre-ordained candidate for the party to rally around. Not since the bitter Ford-Reagan run in 1976 has this been the case. Sure, there have been challengers along the way - Bush I in '80, Buchanan, the leg-pressing preacher - but these were all outsiders.
Here's the list of pre-ordained Reeps:
'80 - Reagan
'84 - Reagan
'88 - Bush I
'92 - Bush I
'96 - Dole
'00 - The Shrub
'04 - The Shrub
There's no way McCain can fit that bill, though he is certainly trying. Pat Dobson has already ruled out McCain. Romney is running hard to the right, but his religion and his past positions weaken him substantially. Then there's Guliani - America's Mayor. Guliani will have a tough time getting through the primaries as many of his positions are too liberal.
There are a number of second-tier candidates - Huckabee, Newt Brownback, and Duncan (or is it Hunter?). I just don't see any of them gaining traction. Hagel is an interesting candidate, as he is the only reep to go against the war (he's been against that mess from the start). However, in the process of being proven correct, many party faithful regard Hagel as a Judas. Unless, Iraq blows up into a full-blown regional war, I can't see Hagel gaining traction within his own party.
The Dem side is also interesting. Sure, they have had some pre-ordained candidates - both Mondale and Gore come to mind. But, who remembers the 1992 'seven dwarves' battle that eventually saw Bill Clinton take the crown? Kerry also came out of nowhere. So did Dukakis.
Hillary is trying really hard to put everyone down early so she can win the nomination. However, Obama is for real and Edwards never stopped running after 2004. Hillary's position on Iraq is going to bloody her for some time. However, she can take some solace knowing that Iraq will likely doom McCain, too.
The wild-card is Al Gore. I just read that Gores has the dosh to self-finance himself into the race. The door is potentially open - particularly if Obama, for whatever reason, falters. Gore is in the process of achieving rock-star status. He could conceivably catapult an Oscar win into a strong presidential bid.
There are minor dem candidates. Biden shot his foot off, so he's a non-starter. Richardson, Dodd, Wes Clark, Sharpton, and Kucinich are other possibilities. However, some of the minor players are already dropping out - notably Bayh and Vilsack.
So the race is on; there are six major players, three on each side. I can envision one additional candidate making a run - Brownstone or Newt on the right, Gore on the left. There will probably be a couple of "issues" candidates who stay in. So, some 20+ months before the general election and the field is at once wide open - and limited.