ColonelCrockett: In my opinion, it depends on who you're playing. I'm a firm believer in playing the man not the board and over the board in matches (rather than here) that can be very effective.

I like to play 2...a6. That's partly because I used to play the 2...a6 O'Kelly variation in reply to 2.Nf3 throughout the 70s and 80s, even against people like James Plaskett, transposing into a Kan if white played c4. An early a6 is often effect as it often gets White out of his normal thinking. That can be good against bookish players or players stronger than you. Against a weaker player you might keep to more classical lines. Whatever you do, don't end up playing against yourself - always a danger with very tactical lines against a weak player when a simpler alternative would have done.

I'm pleased to see that 2...a6 still gets good stats here:
>http://www.chessgames.com/perl/explorer?node=33281&move=2.5&moves=e4.c5.Nc3&nodes=21720.32033.33281

though the sample is rather small. In any case it is NOT a refutation of 2.Nc3. I doubt there is one.