Get the sport. I have a 325i sport and have driven a non-sport 325i and there is a big difference in handling. The wheels/tires are better (which makes the biggest difference), the suspension is retuned for "higher performance" (stiffer, higher-frequency car), and I think the seats and steering wheel are different.
Unless you want a 330i for the "luxury", get the sport (i.e. if you like driving)
Personally I don't understand why anyone would buy a BMW without the sport package.