Planted tanks are great (albeit I'm a tad biased, as all my tanks are planted)! As aokashi said, light is very important to plants and will help picking out what to use. Gravel works well - I started out with gravel, and there were no problems at all. Chocolate and aokashi already pointed out a lot of the good starter plants, so I'll just add a picture of one of my tanks and what it contains:
5.5 gallon betta tank, lighting: single 13W compact flourescent - Water Wisteria, Anubias, Green Cabomba, Compacta, Hornwart
Personally, I like my snails, but I know some people don't. I've found that as long as I don't overfeed and keep the tank clean, the snail population stays in check. lol I actually intentionally introduced some "pest" Malasian Trumpet Snails to help keep the sand in some of my tanks aerated and therefore prevent the formation of anerobic pockets.