Jus thought I'd add my tuppence - generally I'd say all-liquor drinks should
be stirred to keep clarity. They don't need shaking as there is less actual
"mixing" of ingredients to accomplish. To that end, I double strain mine
through a tea strainer to make sure that there are no ice chips in the drink
at all. I think they (manhattans, martinis et al) should be crystal clear - no
bubbles, no "head" no ice.