Well, for new hobbyists. It all depends on what kind of fish you want to keep. If I were you I wouldn't go with anything too small e.g) 10g, or something or big e.g) 55-100g.
For new hobbyists, a 20-29g is necessary.(well imo
). I have to agree with webmoose about buying supplies individually becuase most kits have low quality brands, thats why it's cheaper to buy a kit.
For filtration, I would suggest a H.O.B(hang on back) powered filter, i would suggest aqua clear brands.
You'll need a heater possibly a 50-100watt, submerisble or hang on back.. temperature should stay around 70s...
all deco brands will be up to you.
for lighting, flourescent is best as they don't cause much heat and they have a brighter view instead of incadescent bulbs giving a tint of yellow and causing more heat.
I like JBJ lighting, they are a bit pricey, but it is worth buying them.
anything esle you need to know, please post more questions..