ITC Garamond.
ITC's flavor of Garamond is a bit more roundy and "happy" looking than many of the other Garamonds.
Surprisingly, just about every version of Garamond sold from one foundry to the next is different in subtle ways.
Monotype Garamond (the version bundled in with WinXP) is pretty ugly looking. I like Adobe's Garamond. Their new Garamond Premier Pro family makes good use of the OpenType format and is slightly different from their previous Type 1 version.
Berthold's GaramondBE is pretty decent too. It seems more like a slab-serif Garamond. I can't remember whether I picked that up with Illustrator 4.0 or a PageMaker 6.5 upgrade.