What shoes do you wear for your workouts?

Throughout my life, I've had various times where I've gone out and bought a ton of workout clothing because I was about to start working out. Then I wouldn't work out, and all the money I'd spent on workout gear went to waste.

About two years ago, I started a regular pattern of working out -- and although what I've done in order to work out is varied, I've actually been sticking with it. I've been doing step aerobics, swimming, walking, dancing (ballroom, blues, argentine tango, and latin), and more recently I've started doing cardio kickboxing and a hip hop class at my gym.

With the swimming and dancing, I've either needed very particular shoes or no shoes at all. With everything else, I've gotten by with an old pair of slip on walking shoes. But lately in the cardio kickboxing class and also the hip hop class, these shoes have been slipping off my heel with some of the movement I've been doing.

So....even though I feel like it might jinx me a little (I know it's silly, but it kind of feels like if I spend money on equipment that I'll stop working out)... I do need to get new shoes.

Can anyone recommend a good pair of workout shoes? What do you wear when you work out, and what sort of workouts do you do? What do you like about them?