I really think it depends on you.
1. Make sure your new equipment will fit your goals. (If you're not a power-lifter, you might not want to invest in freeweights, etc....)
2. Make sure you will enjoy using it, or you won't.
3. Make sure it's a quality piece of equipment. rickety exercise machine fall apart quickly, and really aren't fun to use. Spend the money on quality, you will be rewarded for it.
4. Make sure the machine has a wide range of weights, resistance or settings, that way you'll be able to improve and change your workouts around even more.
5. Most important, make sure it's a machine that won't hurt you. If you have bad knees, or back, be careful what you buy.