That's my mind pretty much made up then.
I think I will go for the whole week. I know people have said that they would probably only go for the final couple days if they were to go again, but as this would be my first time I can always say that next year. There's also plenty of other things to do in the region if needbe.
Finally. I'm considering signing up for the one of the hospitality things (perhaps the chequered flag club). I know it's not exactly cheap, but if you factor in a ticket, pit pass and parking each day it's not outragously more expensive. I also read that they have the occasional interesting speaker/lecture throughout the week.