Well there are a couple of things that I would really ask for you and everyone here to consider...
1. It sounds like you may not have the technical ability to set a nice theater up yourself. Many people start with 1-2 thousand dollar systems, or far less, and learn over years, until they build their dream theater. You have the money, but no technical experiece so...
2. You will need to budget for installation labor which is typically a fairly fixed number. X dollars for running wires (regardless of brand) Y dollars for hooking everything up Z dollars for hanging a projector, screen, etc. Add it all up and you are left with the actual amount of equipment you should budget for.
3. I'm not sure what area you are in, but you are talking in Meters, so I'm guessin' not the USA. Another Canadidian? Where at? Maybe some locals can point you to a decent store or invite you over for a cup of tea and a mind blowing theater experience.
4. $30K in Canada is not the same as it is in the US, hopefully people will be aware of that.
5. $30K in Canada is STILL a lot of money and you can set yourself up nicely, especially if you want to do a lot of research yourself and think you might have the technical prowess to do some work yourself.
In your 30 foot square room are there windows? A projection system sounds nice in that amount of space, most people have far less for their home theaters and use projectors anyway. How tall are the ceilings in the room? 8 feet? 10 feet? 12 feet?
If you are at 10 or 12 foot ceilings, you can likely do at least two levels of seating, which is always cool in a theater, but most theater installers can't do tiered seating like that. So, it's a job for a handyman/carpenter to come in a do if you want it.
If you have good light control in the theater area, then I would definitely be looking at a projector, and NOT a plasma. Plasmas are cool, but don't have nearly the impact that a 10 foot screen has. At 15 feet away (5 meters) from the screen, and a decent projector, you are definitely in the real world possibilities for a 10 foot WIDE screen - about 3 1/3 meters wide.
In a dedicated room it is always nice to run wires behind walls, but not necessarily as important as it is in a non-dedicated room.
So... your Sony 60" should stay where it is. If you are looking for surround sound with your Sony, you can go with some decent in-wall speakers, and some in-wall surrounds and even an in-wall, or SMALL subwoofer. Some 10" boxes can be placed under coffee tables at the end of couches or even behind couches to hide them. It can make the one room sound much better and not disturb the rooms integrity almost at all. Think 'inexpensive' A/V receiver for that room and a cable box and dvd player. Likely just a few thousand dollars can cover that one room. Though, if all the wires are run inside the wall, there may be a need for a handyman to fix the drywall and apply some touch up paint.
For the basement, I would look towards a Denon 3805 or Yamaha 2500 receiver (or similarly priced/featured item) one of the lesser-expensive 1280x720 DLP projectors, and some decent speakers with one good sub. Perhaps, an outboard amplifier for your main speakers to really get the audio going if budget permits. Speaker choices are hardly limited, but prices are all over the place. In my opinion, floor standing loudspeakers are the way to go in a theater. In your living room... no, but in a theater, yes. I would get a decent DVD player, but nothing to far into the 'high-end' area. But that's just me. I fully expect HD disc players to be available within 1-2 years and I can wait for HD disc players instead of spending 1,000 dollars or more on a DVD player that I know won't ever match the quality of the chepest HD disc player.
Cables: A good place will likely custom make all the cables for you on site as they put your room together. No 'brand names', but basically the same quality components you find from a company like
www.bluejeanscable.com - I know where I used to work it was all Belden Cable with Canare connectors everywhere. Some places are definitely better than others though, so shop around and pick up your yellow pages.
Finally: Stores typically have stuff you can see, which is nice, but smaller, custom installers and integrators, typically have a much deeper knowledge base than store sales reps do. The guy who is doing it for himself is basing his life on being able to tell you what you need, and knowing how to get it done. The guy at your local high-end store, may only be there to earn a paycheck and not have any vested interest in you getting what you want.
Oh yeah - don't forget to budget for a decent remote control so the entire family can use your theater... including you.
