1066 mhz vs 800 mhz FSB, does it make a difference?

FSB is only part of the equation that results in the ultimate speed of your laptop's processor, the other half is the processor's multiplier. Two processors can run at different FSBs but be the same speed in ghz if they have different multipliers, for example my processor is 400x8 for a total speed of 3.2ghz whereas another (older and less powerful) processor I have is 200x17 for 3.4ghz. As you can see FSB and even speed don't necessarily mean one processor is better.In general a faster one might be better but right now, and especially with laptops, there is a lot of mixture between newer and older hardware in the market.

If you had the actual names of the processors (T5750 core 2 duo for example) I could give you a more definitive answer.

For FSB speed YES.! It makes a hell of a difference, 1066 mhz Vs 800 mhz FSB would be about the same as going from a 2.5 GHZ processor to a 3 GHZ processor. The FSB or Front Side Bus speed of the laptop is the speed of the ENTIRE board and has a dramatic affect on how much bandwidth will be available for each component.So if you are using graphic intense applications in the future I would definitely consider going with the 1066 FSB laptop. Also keep in mind with some machines you can get a lower rated chip now and always upgrade later, but check to make sure this is possible first!