Intel® Core™2 Quad Mobile Processor Q9000 ($348)
2Ghz with 6 Mb L2 Cache and a FSB of 1066Mhz
Then we have the core i7 mobile processor:
Intel® Core™ i7 Mobile Processor i7 720QM($364)
1.6Ghz on all four cores or 2.8Ghz for single threaded apps
6MB L2 Cache
Capable of hyperthreading as well, for a total of 8 logical cores
Has a execute disable bit
Doesn't have a Front Side Bus, instead uses DMI (Direct Media Interface) and runs at 2.5 GT/s (Gigatransfers per second) and the old FSB is going out the door and outdated as we speak...
My Opinion:The Core i7 is a new chip with the newest technology. It uses faster memory (DDR 1333) and has massive memory bandwidth through the Direct Media Interface. They're about the same prices so I'd go for the i7 for sure.
The i7 will smoke the Q9000 in video editing even with a lower clock speed, and especially if your application is single-threaded, then the i7 will blow that Q9000 away.
The i7 also supports more RAM, a total of 8GB of DDR31033(Dual Channel) so upgrades are a possibility.
Intel Comparison Chart:
http://ark.intel.com/Compare.aspx?ids=40480,43122,