well your gunna have to wait at least a couple of months after you cycle your tank to get corals so youll have a well astablished tank.also youll need very strong lighting to hold an anemone and you also should have a very well astablished tank to with all the right readings beacuase they wont tolerate poor water quality
i have a 55 gal also and i put about 3-4 inches of live sand in my tank for biological filtration(get some other opinions on this thow)
the live rock....i think you could put as much as your hearts content(but im not sure)and this will also help with bio filtration
if you are going to have a reef tank you will also need an RO unit beacuase tap water just won't cut it(it has to many bad things in it like metals and stuff)or you could used distilled water for water changes but that could get a lil exspensive
im pretty sure you know about cycleing a freshwater tank but its nothing like cycleing saltwater....im not an expert on cycleing so put up another post on cycleing to find out what to use for the cycle and when to use it
finally you will need equipment and im not an expert at that either but heres what youll need in my opinion:
a pump to return water from the area where the water is going from the tank
some powerheads(maybe 2-3 maxxi jet 1200's)
live sand
live rock
sump
refugium(i think this is optional)
200 watt heater
protien skimmer
uv sterilizer(not sure bout this)
i dont know if youll have a drilled tank so i cant tell you what you will need for an overflow or something
RO/DI UNIT
BUT REMEMBER WHAT I SAID"IM NOT AN EXPERT AT EQUIPMENT" SO GET OTHER PEOPLES OPINIONS
oh yea for what kind of live rock you should get i would deffinately reccomend the live rock off of here but if you go to your LOCAL FISH STORE just get cured live rock(make sure it doesnt smell really bad)and look for rock with coral line algea and try and look at the rock for unwanted critters(aptasia,ect.)
well i hope i helped a little and remember to get other peoples opinions