The kits usually have pretty poor equipment. You'd be better off piecing it together. Here's a basic list you could start with:
20g-40g aquarium - Don't get a smaller aquarium. It's easier to take care of a bigger tank and it puts fewer limits on your fish selection.
power filter - Get one rated for twice your tank volume. AquaClear is a little more expensive than the competition, but they're the best.
Marineland or Fluval heater - You get what you pay for with heaters. These two brands are pretty reliable. Get one rated for your tank for best operation.
Glass canopy - There are several brands. Glass canopies keep fish in the tank, limit water evaporation, and are pretty cheap.
Lights - If you're just keeping fish, just about any light will do. If you think you might be interested in plants, get a decent light fixture so you don't have to upgrade later.
API Freshwater Master test kit - Lets you know what's going on in your tank. It's key to figuring out problems. Strips aren't worth beans. The API kits lasts forever and is more accurate than strips.
Decorations - Don't limit yourself to what you find at the LFS
. The substrate in all my tanks came from Home Depot and Menards. Just do your research to make sure it's safe.
Thermometer - Don't trust what the heater knob says. They're usually not right.
Net - A couple different sizes are nice, but a green, coarse mesh net in a medium size is good to start.
Gravel vacuum or python - You'll need this to clean your tank and do PWCs.
An aquarium-only bucket - You need a bucket that you know isn't contaminated.
I'm sure I'm missing something, but that list is a good start.