kanji:
Amazon.com: The Kodansha Kanji Learner's Dictionary (9784770028556): Jack Halpern: Books (until you're advanced, then you buy it's big brother)
words: buy an electronic dictionary; i haven't ever seen a physical J-E dictionary I thought was really all that good; I had the Random House when I was much younger. But with the Internet and electronic dictionary, I never needed a paper book. I have this, and it is excellent:
Canon Wordtank G50 Japanese Dictionary