I'm in the same boat as you only about 6 months further along. If I knew then what I know now I'd go with this:
The biggest Tank I could afford up front (even if it meant holding off a bit, buying a smaller tank then getting a bigger one later is MUCH more expensive).
Personally I have glass now wish I went acrylic with predrilled for sump system holes already made, and make sure the top holes in the tank are as large as structurally possible as it sucks adding rock, placing fish, corals, and other creatures and general tank maitenance with a small work opening.
Anyone who is accomplished in reefing will tell you sump is the only way to go so start there from the get go.
The most successful modern systems include, sumps with wet to dry sock filters, prefilters in over flows, high current return with these little fittings in the returns for extra water flow (forget the name but their super cheap fittings that suck more water in as the fast water flows through them right before the water releases back out into the tank).
The sump is for extra water in the tank (more water makes it harder to have quick changes in your system, and a good place to do your water maitenance without bugging your happy calm reef tank. It also is where you will want to put algae for added bio filtration, another trick you will learn is how to grow your planktons - they also filter out trates and are the best thing for your reef to eat as this is what they eat in the ocean.
Then the added value of hideing all your ugly heaters, and filters, even your temperature floaties.
Buy a good stand or make one that holds all this stuff in it, buy or make a good hood that has plenty of light space, you will want metal halides, anything less is not only less effecient it doesn't look anywhere near to the light quality and crisp view MH create for you. ( I just switched from PC to MH and will never go back the fish look so much better, hell my sand is prettier!).
Go with LR, even if you make your own for cost (yes you can create your own LR in your own tank but it takes months and months of work but thats another debate). Get at least a pound of Live Rock and a pound of Live Sand per Gallon.
A protien Skimmer is a must have, never buy bio balls, UV filters are debatable but not necessary at all, start slow, never buy more than one new species is my rule. ( After I've successfully kept one of a species and want more I may buy several, specially because several species will attack a second of its kind but not if there are more than 3 in the tank, again another discussion entirely).
Last thing I can think of off the top of my head is 2 things: Fans, 7 to 10 " ones from your local office depot or staples are best and cheapest way to keep your water cool in most situations and keep those MH from heating up the water.
Never listen to your LFS EVER I dont care if he's got a degree in Biology (true story).
and most importantly JOIN YOUR LOCAL REEF CLUBS, they are a life saver (of many aqua species each day) they do lots of local trading with eachother and know all the deals and cheapest routes to success.
