The SHOT is a dead virus. The nasal mist is a weakened live virus. Because my wife has a chronic immune disorder (Type 1 diabetes), I am not allowed to get the mist and must get the shot. It's highly unlikely the mist would cause her to get the flu, but better safe than sorry.
WP - get the mist. No needles and you're vaccinated. Most of my co-workers get that and none get sick.
I think H1N1 is only a needle option.