If you really want to improve your game, go have a custom set of clubs made. I will never buy another set of clubs off the rack again.
The club heads are less important than the shafts. Club heads come in 3 basic types. Forged blades, Partial Cavity backs and Cavity backs.
Generally, the pros play with blades because they are slightly longer and you can work the ball (spin it) more with blades. However, they are a lot less forgiving. You have to hit the sweet spot for them to react well.
Cavity Backs are for the recreational golfer looking for a lot of forgiveness and less spin. Off center hits will still fly straight and true. Because of this they offer less spin.
As a 5 handicap looking to play a lot of golf, I'd be thinking about blades or partial cavity backs so you can work the ball when you want to. But no matter what club head you choose, make sure you buy custom fit clubs. They make a lot of difference.
We are lucky to be alive during Tiger's Reign. We are able to witness first hand an athlete who posses the skill, desire and focus required to dominate modern golf.