First of all, decide if you wish to drive a rear wheel or front wheel drive vehicle. If you do not know the benefits and faults of either, then just stick with the Acura... it will save you money and you won't crash it in the rain.
If you decide to choose a RWD vehicle, of course, the BMW is incredibly attractive. After all, the 3 series is the sport saloon that everybody else wants to emulate. Sure, the Infiniti will be more powerful, but it is a first generation vehicle with limited feedback... besides, I think it's quite unattractive. The 330 is an excellent choice for an driving enthusiast and comfort seekers alike.