WOW! By the way i am only 12

so thats why i can't afford a huge tank. So i wouldn't need a protein skimmer.... over here they cost £70+ and possibly not a filter which is £30+ and i was expecting only to have 1-2 really small fish or mabye a really small seahorse

I would definately go with clownfish cos they are just SOOOO cool. all i really want is a little chunk of live rock and a few hermit crabs a shrimp some coral and 2 clowns. i agree with u on the anemone thing, i have dun sum research and they do need alot of room. i don't really know the difference between all the different types of corals, they all look the same to me.
I probably would have a filter on it because for the extra £30+ it saves ALOT of hassle in a house as small as mine. What i really want is lots of little organisms with little living things that you can see crawling in and out of holes and such, it just really appeals to me, as long as it's not boring and times when nothings happening.
I would prefer stuff thats not poisonous, but hey i'm not picky. I would much prefer a tall tank, they're more compact.
Does a marine tank have to have fish in it to have stuff like coral and inverts?
Well thats all i have to say for now.