Well i'd be bummed, infact, it's specifically why I waited for the C2D.
And don't really buy that C2D isn't much better, most benchmarks have a 10-25% increase, which is actually significant.
With that said, depending on exactly what your doing, odds are the CD is going to be able to fulfill your needs, after all it's still an excellent machine. Top of the line doesn't stay top of the line for very long, and as others have said, when you get a computer now a days you need to understand that before it loses that shiny new feeling for you, it'll be outdated to someone else.
Also odds are if your on these boards now, you were aware an upgrade was coming up, so at some point you must have made peace with the pending improvements.