For what it's worth, I've set up a 300G tank this year for considerably less than some of the figures quoted above. Here's the breakdown (the figures are approximate):
Custom Tank with overflows + shipping: $2000
2 2x400W PFO Retro kits/sockets/reflectors: $480
4 Iwasaki 400W bulbs: $240
2 4-lamp LN VHO kits (ballast + caps): $280
8 vho actinics: $160
Sump (diy 60G acrylic): $120
Dolpin Return Pump: $330
2 1" sea swirls: $340
2 Gemini pumps: $140
Bullet 3 skimmer and pump: $650
Calcium Reactor + regulator: $650
Heaters: $100
Assorted plumbing/electrical: $200
300 lbs. uncured live rock (cure it yourself in a plastic children's pool with the Bullet): $900 (including air freight)
600 lbs. dead sand (the price varies alot depending on whether you can get southdown, are will to use some silica sand, etc. I did both and spent about $300--partly because southdown on the west coast is spendy, partly because I used about 200 lbs. of "Oregon beach sand"--but alot less than using all Caribsea, etc. (I did not get a diatom bloom from the beach (silica) sand.
100 lbs. live sand + shipping: $250
Miscellaneous: $200
If I've added correctly, all of the above comes to a bit over $7300. Don't what stands/hoods run, but if you can get one for $750 (I built one for less), the total should be somewhere around $8000 without snails, corals, fish, etc.
All of the above assumes that you're willing to do some electrical and plumbing work, as well as work with acrylic. If not, then the cost goes up accordingly. I'm also sure you can do better than some of the prices I have quoted; building your own skimmer or calcium reactor (or ordering one or both from someone like Myreef or Geo on the net) will reduce the cost considerably.
I realize this is pretty crude, but perhaps this outline of my costs setting up a similar tank will be helpful.
George