A high-light, high-growth planted tank requires CO2--you can get a yeast-and-sugar generator for about $40 or do it yourself (see
www.thekrib.com for more information). Otherwise you can grow many plants with low light. If you have high light without CO2, though, you'll be fighting with algae.
A plant substrate is worthwhile--J&L carries Flora Base at a fair price. Plants eat fish wastes, so at least one fish from the start is good. Shrimp (eg. red cherry or Amano) are good for cleanup and fun to watch.
Planted tanks can be a bit tricky and expensive to set up, but pretty easy once they get going. Water parameters aren't so critical and the only maintenance is changing water and trimming plants.
Regards,
Nevin