Ya, check out the Koralia powerheads. You usually need two powerheads in a tank that size to keep detritus from settling. I would suggest two Koralia 1 powerheads.
Like mseepman, I am a strong believer in protein skimmers as well - at least definately for novice keepers, and I would suggest not using a canister filter. If you would like to run carbon and phosphate media you can use either a PhosBan Reactor (my first choice), or a cheap hang on power filter like the AquaClears. Look for about 100 gph flow rate for the phosphate media. I would strongly advise against the Prism protein skimmer as, in my opinion, they are only good for disposal. A good protein skimmer for a tank that size would be a Tunze Nano Skimmer 9002 (about $180). This is a very good, high quality skimmer that works very well on nano-sized tanks. If you are unable or unwilling to spend that much money on your tank then I wouldn't bother at all with a skimmer as in my opinion, a poor skimmer isn't worth spending your money on. 20 lbs of live rock will probably be enough for your tank.
Marine refers to anything saltwater, but generally refers to a tank with no corals. Reef is a tank that houses many corals and fish. FO is fish only. FOWLR is fish only with live rock.
Personally, I would also replace the aquarium gravel with sand. Look for aragonite sand like the Caribsea Select. It doesn't have to be "live", which I think is a very well done marketing scam.
As for reading material, as mseepman graciously suggested, the articles in my signature are good resources for novice keepers.