As I am a Defense first guy, I would start with:
1) Steve Alfords 8 Essential Progression Drills for a Man To Man Defense. I love this disc and how much he stresses stopping the dribble first.
2) Now, you need a man offense. I like the Open Post Motion so I would recomend Bob Huggins Open Post Motion or Jerry Pititgoes video on the same topic. If you are a 3 out, 2 in guy, check out Dave Loos 3 out, 2 in High Low. If you like 4 out, 1 in, I really like Pete Carril's first tape on the Princeton Offense and Dennis Felton's disk as well.
3) Next, I would go zone offense. I like Coach K's Attacking the Zone video. Also, Jack Bennets Zone Motion disc is great.
4) Now, if you want to add some Zone Defense, Jim Boeheim's 2-3 Matchup Zone is really good. I am not a zone guy but after watching it, I put it in for special situations.
5) Lastly, you need some individual fundamental stuff. For individual skills, there is a lot of good stuff out there but I really like Rick Pitinos Basketball Fundamentals DVD.
Good luck,
Coach LeClaire