The books in Seirawan's Winning Chess Series are great. There's one on tactics and one on strategy.
A game collection like Logical Chess Move by Move by Chernev or Understanding Chess Move by Move by Nunn give you a little of everything as they give at least a short comment on every move of every game covered, and are good books.
I have saved up some money, and I'm looking into buying some new chess books. I just need some direction on where to find them and what to buy