Looks like the SQL 2008 price is staying the same as 2005. Interesting to note that many customers have not even upgraded to SQL 2005 yet. Launching 2008 should speed adoption of 2005. Customers always seem to want to stay 1-2 versions behind because of the appearance of stability & being a "proven" architecture. In my opinion there is no reason not to ditch SQL 2000 for SQL 2005, if you have any need whatsoever for better reporting and performance capabililties.
Using 64-bit architecture and the increased memory capacities of SQL 2005 Enterprise should net some serious performance improvements for those who upgrade. Not to mention the management views that will make analyzing and boosting performance in systems much easier.
Hopefully they launch the first service pack a month after, so that the early-adopter crowd will go all in on an upgrade.
One feature being hyped is "Pervasive Insight". This appears to be the external auditing capabilities that wrap around the database. There also appears to be some integration of the BIDS add-in into the base platform, to troubleshoot issues with dimension relationships and warnings in Analysis Services.
More info below.