Welcome to FishLore!
First off, you've got to figure out how big your tank is. If you go to the top of your screen, you can click on the FishLore logo and get lots of info on the hobby. There's a link there called, " Aquarium and Fish Tank Volume Calculator" which should help you figure out your tank size.
Your filters look like undergravel filters (ugf), and will need powerheads to make them work. They pull all the crud down below them and it's kept there forever. Most hobbyists don't like this type of filtratration because the crud never gets removed, and like Boxermom said, they pretty much limit what types of live plants you will be able to have in your tank. Any live plants you put in your tank that have root systems in the gravel/substrate will not do well because all the nutrients will be sucked away before they have a chance to absorb them. What you could do though, is reverse the flow of the water so the powerheads suck from the bottom up, and have hang on back (hob) filters on the tank also to filter the debris. I still think this would limit your live plants in that tank though.
If you decide to change your filtration, once you determine the size of your tank, you will be able to determine how many gallons per hour (gph) you need for adequate filtration. Most hobbyists recommend 10 times the gph rate on your tank for power filters, and 5 times the gph rate for canister filters. Don't be fooled by what the box says in reference to what size tank the filter is good for. Look at the gph instead. The power filters hang on the back of your tank and has a tube that sticks in the water. A canister filter actually sits under your tank, and all you see are the intake and outtake tubes. Sponge filters are also good and very inexpensive to use. Easy to clean also.
I would not recommend a saltwater tank at this time. You are probably overwhelmed at this time, and saltwater is more expensive and complicated than a freshwater tank would be. If you like the hobby, then it could be something you plan on in the future.
Make sure you understand cycling completely. In the beginners forum, you will see a sticky called, "FishLore Article for Beginners". Anything you don't understand about cycling, please ask. This is the most important aspect of fishkeeping, and will determine whether your fish live or die. You have seen a couple of posts about bio spira which is really great stuff. However, I don't usually recommend it for newbies because cycling your first tank is such an important lesson on understanding how a cycling works, and if you go through the process, you will know what to do when your readings are less than perfect in your tank. I have used the product 3 times in emergencies with great results, but that was because my fish were at risk. Most hobbyists recommend you fishless cycle because the cycling process is very stressful to your fish and could kill them.
You definately need some test kits to get started. I highly recommend the Aquarium Pharmaceuticals master test kit. It will have all you need to get started. If you live in the states, copy the page with the master test kit on it on the PetSmart web site and take it to your local PetSmart store. They should honor the online price, and this will save you over half of the cost. I think the online price is $13.49. They normally sell locally for around $30.00.
You will also need heaters for your tank, unless you decide on goldfish or white cloud minnows. Any tropical fish you decide on (including bettas) need a heated tank. Once you determine the size of your tank, you will need to have 5 watts per gallon to heat your tank properly. Your tank will need at least 2 heaters to heat it more evenly. So if you have a 50 gallon tank, you will need 250 watts, and most likely 2 125 watt heaters.
Live plants are wonderful, but they do take a little care. I would definately go for the low light plants. They are the easiest to care for.
This article will help you decide whether you want live plants or not:
http://www.plantgeek.net/article_viewer.php?id=17
Let us know what size tank you have, and the folks here will gladly give you ideas on what to put in that tank! This hobby is so much fun, but it takes a lot of patience and preparation to be successful. We will do everything we can to make this experience enjoyable for you!