I wanted to bump this because I think it's a great thread idea.
Carlos Delgado - .287 first half hitter, .319 second half.
Garret Anderson - .272 first half, .319 second half.
Scott Rolen - .275 first half, .293 second half.
Javiez Vazquez - 4.22 ERA first half, 3.29 ERA second half.
Bartolo Colon - 3.87 ERA first half, 3.32 ERA second half.
On the other end of the spectrum -
Jose Vidro is a .341 first half hitter, and .297 after the break.
Luis Castillo is a .323 first half hitter, and .274 after.