I have taught an adult small group Bible study class (ages 35+) for about 10 years and am always looking for good study material. I usually try to find a study that I'm interested in and teach it to the class after I've completed the study myself.
I stumbled across JesusWalk when I was looking for a pre-Easter study, and used Lamb of God during Lent (the 40 days before Easter Sunday). Dr.Wilson is very detailed in the history and background of Jewish history and culture, but he teaches it in a way that is easy to understand, easy to teach and easy to apply to daily life. In this particular study, he details what Jesus was doing in the days leading up to His crucifixion (and why it was necessary) from New Testament accounts, by tying in what Jewish culture practiced in the Old Testament, which made everything Jesus did even more amazing. For me it was a fresh look at the stories I'd heard about every Easter, but in a way that changed how I understood them.
If you are looking to learn more about the Bible, the JesusWalk studies are fantastic. Dr.Wilson is well educated and is a great Bible teacher. I highly recommend his studies.