KITCHEN BLEG: I’ve got some pretty decent, but not top-quality, kitchen knives. My brother recently bought some much more expensive ones, and says the difference is big. I’m thinking of upgrading — I do a lot of cooking around here — and wonder if there’s really a big difference between, for example, these high-priced Wusthof knives and these “budget” Wusthof knives. Any other suggestions also welcomed.