Here are the official prices from BMW Germany (as of June 2007) for the 2008 M3 - Please keep in mind that this price is the German price (not US cost) but will give all of us some reference. Enjoy.
Fahrzeugpreise (Prices are shown in EUROS!!!)
Das M3 Coupé ist serienmäßig mit einem 6-Gang-Schaltgetriebe ausgestattet.
(Says - comes standard with a speed manual)
EUR* 56.008 ohne MwSt. (w/o 19% luxury tax)
EUR* 66.650 inkl. 19% MwSt. (with 19% luxury tax)
Here is the converted German price -> US $ Dollars
Like I said before this is the German price and not what the M3 will cost here in the US.
Currency Conversion Results
Jun 15, 2007 EURUSD= EURO 56008 US $ 74,591.- 
Exchange rate : 1.3318 US Dollars for 1 EURO
I suggest we compare the German price of a 335i (fully loaded) to the base price of the M3.
In comparison, the base price for a 335i = EURO 44650 US $ 59,735 
So, it looks as if the difference between the two cars (calculated using base price)
is
$ 14856.
BMW 335ifan
Hope this helps.
BMW335ifan (maybe new M3 fan) have not bought the car yet - waiting until next year.