Depends on what you are shopping for...I've used craigslist for a few things (rented apartment, bought a few used cars, some other household odds and ends)...but I haven't used print classifieds in...well, over a decade.
it depend what you are shopping for, i have used craigslist for alot of my shopping, clothes are...ugh just don't try it :P but animals and animal supplies i've gotten great deals on all that stuff :)
They're great sources if you're looking for very specific things, and also looking to save some money on it. Remember, its also tax-free.