Disagree. Rockyou dictionary is nice but far not the best. The Hashkiller Output Wordlist combined with rockyou-30000 and best 64 is the best precompiled dictionary i've found yet. You can still do better but it already rocks a lot. And who knows, maybe it contains the Rockyou list anyway 
Though logistix is right, you need to know what and who you attack. Real password lists are fine to get a lot pwds fast, but depending on whom you wanna attack, constructed word lists with normal words of lots of languages (+real names, surnames, cities etc. you name it) combined with clever rules can be much more effective to cover all sorts of common password contructions. It's just a wide field and, disagree with logistix, by far more worth than stuffing another GC in your rack.
There is a very good explanation I think by philsmd how he thinks a good wordlist should be build and how you do that. But I'm too lazy to look for it now, you find it somewhere here in the forum.
Personally I didn't try princeprocessor yet and have it on my task list. Curious how it compares to a "normal" pattern of attack methods.
Though logistix is right, you need to know what and who you attack. Real password lists are fine to get a lot pwds fast, but depending on whom you wanna attack, constructed word lists with normal words of lots of languages (+real names, surnames, cities etc. you name it) combined with clever rules can be much more effective to cover all sorts of common password contructions. It's just a wide field and, disagree with logistix, by far more worth than stuffing another GC in your rack.
There is a very good explanation I think by philsmd how he thinks a good wordlist should be build and how you do that. But I'm too lazy to look for it now, you find it somewhere here in the forum.
Personally I didn't try princeprocessor yet and have it on my task list. Curious how it compares to a "normal" pattern of attack methods.