I have "bought" myself the SRD 3.5.
I am evaluating if it's the case to buy the books, in which case I think it'll be all 3, but our gaming group is 90% going to continue the campaign with the same 3.0 rules.
I think the 3.5 books costs too much compared to how much I spent for 3.0, and in fact I have been trying since a few months ago to find out what's in the september gift package of the 3, and how much it will cost.
If it costs less than the 3 purchased separately and has already some errata fixed, it's possible that I would buy it. I could also afford a few Euros more if it has dice in the package, but NOT if it has miniatures.