Of course stirred. Really, the whole shaken thing is mostly for show-off sake - what would bartenders do without the prolonged, theatrical shakes? Martini is a gentle cocktail, only two ingredients, delicate balance between them - and then you go and violently shakes them? It definitely kills the whole structure of the drink.
When you stir a martini gently, you allow it to continue to evolve in the glass, or as I've recently tried - in a hip flask. Yes, I know it sounds odd, carrying a cocktail around in your flask, but it works.
And btw, a "vodka martini" isn't a martini. It's a completely different cocktail, so go ahead and shake it all you want.
