Moonlight Mile by, Dennis Lehane. I read Lehane for the first time last year and was hooked. I haven't caught up to this work yet, but Borders had the $27 hardcover on sale for $10. Can't pass that up.
Savages, by Don Winslow. Like with Lehane's A Drink Before the War, Winslow's The Dawn Patrol hooked me on a new author. Your reaction to the first sentence of this book will immediately tell you if the book is for you or not.
Once Were Cops, by Ken Bruen. Bruen is another writer I've been meaning to read. Again, $16 book for $6 is an easy buy.