Free Prize Inside is definitely a great book for people who are into marketing. Its by Seth Godin, the same author as Purple Cow. Its like totally crazy but at the same time he talks about tips that are so basic most companies over look them when putting a marketing/advertising plain into action.
Never Eat Alone by Keith Ferrazzi
Permission Marketing by Seth Godin
Book Yourself Solid by Michael Port
How To Win Friends & Influence People by Dale Carnegie
Stirring It Up: How to Make Money and Save the World by Gary Hirshberg
Let My People Go Surfing by Yvon Chouinard, the founder of Patagonia
The Last Lecture by Randy Paush (even though it's not directly business, it can surely apply)
Hey guys, saw this interesting e-book someone might want to check out it's Outrageous Marketing Ideas for people in the music industry. Pretty interesting
While I don't have any great book ideas at this time, I can suggest a website to use to purchase them if you are interested in buying one of them: BookDealFinder.com.
One book I have read that I did like was one by Dale Carnagie. I think it is called "How I Raised Myself from Failur to Success in Selling".