First off...a very sincere WELCOME!!!
You've just taken the most important step to a healthy tank! you joined TRT!
hehehe
Seriously, you're gonna love it here...everyone is SO nice and helpful! Glad to have you with us!
now...on to your questions.
First...I'd always recommend a bigger tank. Get the biggest one you can afford! hehe. Funds and location/room should be the only limitations to the size of your tank.
The more water volume, the easier this will be (or the longer it'll be until you have problems..heheh)
the 33 will be fine...but you'll find in a few shorts months, that you'll wish you had a bigger tank. however, there are a lot of people on here who have AMAZING nano (small) tanks. So it's purley a preference thing. however..I do suggest that anything else you buy (lights/skimmer/etc), you keep in mind that someday (sooner than you think), you'll end up with a bigger tank. So instead of buying a skimmer rated for a 33 gallon tank, maybe buy one rated for much more! (you can't over skim).
Now...as for Live rock...general rule is .75-1.5 pounds per gallon. It depends on how pourous the rock is. The more porous (bumpy/grooved), the less you need. Generally, I tend to just shoot for a pound per gallon.
Lights...hard question to answer. This depends ENTIRELY on what you want to keep in the tank. If you don't want any corals (fish only), then you're regular florescent lights will be fine. If you do want corals...then what type? Some of the SPS/stonies require very intense lighting, so you'd want to go with
Metal Halide lights. If you want the LPS/soft corals, then you won't need as much light, but still somewhat intense. So you could get away with PC (power compact) or VHO (very high output) lights.
Skimmer...another hard question to answer. Suffice it to say that THIS is where you do NOT want to skimp. My suggestion (and many to follow), is to get the best skimmer you can buy! The better the skimmer, the easier everything will be in the long run. Crappy skimmer means very frequent water changes, algae problems, melting corals, etc. One of our sponsors has what are considered to be one of the best line of skimmers available. Check them out:
My Reef Creations
My biggest suggestion, is to buy and read this book:
Aquarium Corals (even if you just plan on Fish only, there is some excellent information in this book) and
look at our suggested books for more.
Read, research, and ask lots of questions on here. Everyone is very helpful, eager to share information, and help your tank.
Welcome again!! Glad to have you!