I think it's tougher to get a good discount on a high end bike like that than on most bikes. Most dealers keep a very low inventory of these bikes so waiting for them to discount may mean losing out on the purchase to someone who is willing to pay more. Your best bet is to look between now and December for this year's model, because when the 2008 bikes arrive is when bike stores are more likely to deal. This is especially true if the newer models feature a substantial re-design (like the Trek Madones for 2007, which are now going for relatively cheap around here because of the complete overhaul for 2008). I still wouldn't expect any miracles.

A second option is to keep an eye on eBay and the various online classifieds between now and the end of the year, as some bike stores who do liquidate their inventory choose this route.

Keep in mind that many bike stores include "soft" extras such as free adjustments for a year, discounts on accessories, and a fitting when you buy with them. Also, if you go the LBS route you should have warranty protection on the bike, while bikes bought via classifieds or eBay rarely do. If these things are valuable to you, be sure to account for them in your purchase decision.

(Always check out what warranty and crash replacement coverage a bike has. Some companies offer lifetime warranties against defects in the frame, while others may be limited to a year or two. Crash replacement is similarly all over the board.)