As BB explained perfectly you have to buy smart, and this summer has not been very smart. About the 5 years of Rafa's project, I cannot say the players he has brought haven't been smart moves, when it comes to the top players we have.
One thing must be said, buying smart with less money is not easy (1). Due to the multiple sackings of managers in Spain I have seen a few managers. And almost none of them get right all their decissions, that's impossible. The exception of this rule is John Benjamin Toshack. I can't remember a signing of his that was bad. He's got a exceptional eye for that. He's antirotationist too. So there you have a smart buyer, an antirotationist, and a man who knows and loves Liverpool through and through.
Seems perfect no?
The problem is that I have seen Toshack's training sessions too. He doesn't believe in goal coaches. He doesn't believe in physical coaches. He wants the total control of the training sessions. He'll use the youth system against the population's beliefs. He'd use Insua a lot earlier than Rafa. And we'd see his tactical book from the eighties too, Toshack was the one who still believed in sweepers in the nineties.
My point is simple. If you want a non rotationist and a smart buyer, Toshack is one. But I don't think he's the man for Liverpool in year 2009.
If you want smart buyers, and modern coaches, that's a difficult equation, as I have seen very few men getting right every decission. We'd have our share of Dossennas too. (And probably Keanes, because Toshack also liked Keane's signing)
(1) And Spanish teams that have the philosophy of buying cheap, selling expensive, stay in primera 3-4 years pretty well, then when one "bad summer of signings" come, they get relegated.