i would really like to start a coral population in my 55 gal. I only have 1 T5 10000K HO flourescent. Can anyone tell me if 5 watts per gallon is too much? I think 275 watts sounds a bit much, but i could be wrong. I hear that corals need serious light to survive.

5 watts a gallon is actually closer to the minimum than the maximum for the corals. They need a TON of light. Just think about where they are and how much direct lighting they receive. Thats what you have to match. You may actually have to increase your lighting on that 55 gallon or put your coral mostly under the main lighting. 275 watts is close to what you'd need for a 20 gallon tank really.

+1 to phys, but I think it really depends on the type of corals you are planning on. If you want SPS you are going to need a ton more light than if you want just softies. but then if you have enough light for SPS you can keep everything else, so thats a bonus.

i am a beginner, so i will start with softies..
was looking at some "Maidens hair" (SP)
Purple polyp (birdsnest)
orange guttatus (birdsnest)

I don't know really ANYTHING, and like i said, i was hoping to pick some brains regarding this stuff...

does anyone know much about these specific types of coral/plant?
can they live together?

THANKS EVERYONE

Softies are a great start and as kaiden said, they do not require as much light as sps or lps. I do believe birdsnests need a lot of lighting tho. I may be wrong, but be sure to find out before you buy them and they dwindle. You may get away with putting them toward the surface of the water directly under your light. One other issue with SPS and LPS (like those birdnests) is they require a very well maintained tank with plenty of calcium and other mineral. So good habits and knowledge should be learned before buying them so you dont kill them off.
BTW, how much does your MH cover on that 55? I finally wired up my LED today on my 20 gallon and (with a bit of worry when some fuses blew and NOBODY in town had some this time of night) it actually looks really good and hopefully bright enough.

here's a few links to help you out on those coral/plant you listed:
Maiden's Hair: Saltwater Aquarium Algae for Marine Reef Aquariums: Maiden's Hair Plant, an issue i see with this is if it dies, it may toxify your whole tank killing a lot of life... be careful.
Purple Polyp: Saltwater Aquarium Corals for Marine Reef Aquariums: Purple Polyp Green Birdsnest Coral - Aquacultured CCGC 30 Day, it says 3 watts per gallon but maybe more but its a good starting point i assume...
Orange Guttatus: Saltwater Aquarium Corals for Marine Reef Aquariums: Orange Guttatus Birdsnest Coral - Aquacultured CCGC 30 Day

+1. I also recommend zoanthids, mushrooms, and xenia. All are great starter corals and work really well as sort of filler corals in between stuff. They also grow extremely fast. I also recommend candycane corals and frogspawn. Those are going to need a more established tank, so maybe after a few months you could add those. they mak nice additions to the tank.