Alright. Where do I start?
I was in your position a number of years ago. I felt overwhelmed by all the different possibilities of speakers, receivers, separates, amps, players, etc. Not to mention room acoustics. If I were you (and I was you) I would focus on one thing at a time.
I'd start with picking out what room will house your system (sounds like you've done that). This will determine the size of speakers, amount of power, etc. that you will need.
Next I'd pick speakers. Speakers must be matched to the size of your room. If you have a large room, make sure you have speakers that will be able to push enough sound to fill the space. Your room is fairly large. Ask around the forums, state how much you want to spend (do yourself a favor and multiply you budget by .667 so that all the suggestions for spending more than your budget will fall in your budget) and size of room, and you’ll get more suggestions than you’ll ever need. Better yet, use the search function and read all the other answers to the exact same question asked here daily.
Next I'd pick the receiver of pre/pro. The size of your room, the type of speaker, impedance of speaker, efficiency of speaker, and the number/type of inputs/outputs will guide your decision. 4 ohm highly inefficient speakers need a lot of power, 8ohm highly efficient speakers don't. Plan on connecting a bunch of equipment? Make sure the receiver or pre/pro can handle it. Oh, and don’t forget to include 5.1, 6.1, or 7.1 and processing (DTS, Pro Logic IIx) in your equation.
Lastly, I'd worry about room acoustics. I say deal with this last because 1) it's the most confusing, 2) you can only do so much on a limited budget. If you said that money was no object, I would suggest that you build the perfect room first then worry about everything else. For joe average (like me) I have an imperfect room, with tons of acoustical issues, and no chance that I'll be able convince my wife to make drastic room modifications. Get the equipment first, then figure out what you can do to make the room as good as you can.
You'll notice that I didn't mention displays, dvds, cds, TiVo's, etc. I feel that these choices are a lot easier to make. How far back from the tv are you going to sit, multiply that distance by .667 and that's the largest screen you should get. Do you want HD? Is SACD or DVD-A important to you? Do you want TiVo? These are yes or no questions. From that point it is just figuring out which unit(s) have the features you want for a price you can live with.
If you take these things in steps, rather than trying to decide everything at once, you’ll ensure that you are considering all the things you need/want, are not overlooking something (like number of inputs, speaker impedance), and are not overwhelmed by all the choices out there.