Advice for first bike: new or used (specialized allez elite vs cannondale r2000)

Hi...

This will be my first real road bike purchase so, apologies if this
sounds a bit silly. I'm looking to buy my first real road bike in 15
years (Im 31). I will be using it for a triathlon here in California
in Sept. Afterwards I hope to integrate some touring(w/camping), but
Ill never do any racing. My budget is $850 for bike + $150 for
everything else.

I'm looking at two bikes:

1) New Specialized allez elite 2004 triple. Can get it at my LBS for
$850+tax which seems like a good price. (is there a way to stop the
clicking of the derailer?)

2) A good condition used 1999 Cannondale R2000 with Ultegra, Cane
Creek Crono Wheels, Reynolds Carbon Fiber Fork, 3T Prima 199
Handlebar, CP Pave ergometric seat. Asking is $800. Its from a guy at
work and the bike has been taken care of, and the size is right.
Here's a pictu http://us.f2.yahoofs.com/bc/409afe82...ZPOvABkWXm2Vy8

I ruled out the Giant OCR1 since it didnt seem to fit as well.

Assuming both bikes fit me well, which would you go for? I think most
would say go for the new bike, but I think the cannondale might be a
better deal. I still have my '94 cannon MTB and I think they make good
stuff; brother swears by specialized. Either way, Im going to be
happy.

Thanks in advance,
matt