THT: What Makes a Home Run Pitch?
The Hardball Times' Jonathan Hale puts together a terrific analysis of what pitches leave the mark most often by location and type. That there is just one of the many awesome graphs in this post. Sliders three feet off the ground are the most popular pitches to hit home runs on.
Righties also really, REALLY, like to destroy inside changeups, and inside curveballs from right handers.
Hale puts together some nice summaries from the data:
1. If you can spot a pitch on the very corner, be it the very bottom of the zone or right on the outside corner, then there is a miniscule chance that it's going to leave the yard.
2. All pitches left high are home run pitches, not just offspeed ones.
3. Down and away isn't many a pitchers bread and butter for no reason, as both are very important to sap home run power.