Garland:
Can you be more specific? On many par 5's, I start with the same basic choice I make on many par 4's--whether to hit driver or something shorter but more accurate. That choice depends on a lot of factors; on a par 5, one factor is whether I could even reach in 2 if I hit driver. If not, then depending on other factors I might opt for a shorter club.
What I would best like to see is decisions based on having a better second shot to set up the third. Your suggestion of "If not, then depending on other factors I might opt for a shorter club." makes me want to know those factors that would make you choose to use a different club than driver.
Perhaps I'm somewhat of an outlier because I'm more accurate with my three wood (and hybrid) than my driver. Or perhaps I'm missing something. But on a true 3-shot hole, I'm usually thinking about whether the benefit of hitting driver--a potentially shorter/easier layup--is worth the risk of missing the fairway or worse. It's a similar calculation I make on many par 4s, i.e., is the benefit of getting a shorter second shot worth the risk of a wider dispersion?
Take, for example, #9 at Congressional (before the renovation at least--I've only played it once since they reopened). It was close to unreachable from the longer tees. You really didn't want to miss the fairway on your drive because of some bunkers in the landing zone, the rough, and some contours that could make for difficult stances off the fairway. In addition, hitting the fairway with your layup was very important because the fairway was benched into a slope; if you missed fairway, you likely had a lie with the ball severely above or below your feet. And oh, there was a severe little valley from about 100 yards to 30 yards from the green that was maintained as rough. So working back from where I wanted to be after my second shot--about 110-130 yards from the green in the fairway--I had this decision on the tee: hit 3-wood, thereby increasing my chances of being in the fairway but with a longer second shot; or hit driver, shortening my second shot but increasing the chance it was being played from a tougher spot than the fairway.
That may be an extreme example, but I think the point is often true, for me at least: once I know where I'd like to be for my third shot, I'm presented with the basic question of whether driver is the best play for me to get there. [size=78%] [/size]