Since last month, the news is that only 64 bit versions of Vista will run on EFI, so Vista-booting on an intel Mac is unlikely without interesting patches/hardware hacks.
Therefore, running an MS OS on an intel Mac will require some sort of VMWare-like scenario or an update of Virtual PC. Somehow I feel the former is more likely to be the case.
Unless you're a gamer wanting to run PC games at native speeds, I would have thought that the ability to run Windows on an intel Mac without rebooting would be an acceptable course of action (minimise effect of malware, ability to restore from a saved image, speed and convenience of switching).
If other forums are any indicator, there seems to be an awful lot of interest in a MacBook Pro that can run multiple OS's, so if you're patient, the options will come.
soi la, soi carré