I love small marine aquariums! I have kept several 5 gallon and 10 gallon aquariums over the years, and definately would encourage you to try SW
With a 10 gallon, I would not buy a kit, instead put together your own. If money is not an issue, then live sand, live rock, and a small protein skimmer would be the perfect setup.
If money is an issue, then use a Penguin BioWheel filter, with crushed coral as substrate. You would treat this setup like a FW
tank, doing a weekly 2 gallon water change. You will need to replace evaporation almost every day to keep the salt level constant. Monitor Nitrates prior to every water change. If Nitrates exceed 40ppm then do a 5 gallon water change. Hopefully this will only occur a couple of time per year.
Foolproff fish options:
1 Coral Beauty Angel & 1 Perc Clown (Nemo)
1 Perc Clown & 1 Six Line Wrasse
2 Perc Clowns.
1 Sharp Nose Puffer.
I suggest that you choose only 1 option and do not mix and match. These are the easiest SW
fish to keep in my opinion and would make a great small setup. Fish to avoid in 10 gallon tank: Manderine Goby, Damsels, Chromis, Blenny's.