What should I get for my first audio system?

I live in a NY apartment, and I would like a good value system that I won't outgrow too soon (or can move to a 2nd system if I become a audiophile). I'm comfortable buying good used equipment.

-thin floors (avoid subwoofer?)
-would like to play all music from a computer (but my iMac is another room)

I've done some research and here is my current understanding:
1) Source:
-best would be a dedicate laptop in the room loaded with Apple Lossless quality music (>600 kbps)
-Next option is the Wadia dock for my iPod
-Finally, Airport express to send music from my iMac desktop

*Seems like buying a used MacBook is the best?

2) System
-The Decco device (DAC/pre-amp/Amp) seems like a good starter system. It puts out 50W, so I'm not sure what are the largest speakers it can support?
-Can I boost this with a power Amp to support bigger speakers?
-Or, I can buy a DAC and get an integrated amp (like the Creek 5350?)

*Seems like $800 for the Decco is the discount start, which I can then upgrade with a power amp, and then replace with a better DAC and pre amp over time?

3) Speakers
-Two people have recommended the Totems Hawks as having a full range without needing a subwoofer (to avoid annoying the neighbors)
-I'm not sure if a 50W Decco amp can support speakers with recommended power of 30-120W? Should I go for the smaller Arro or Sttaf speakers?
-Or, I can put monitors on stands. Would this give me same quality of sound with less sound traveling through floors?

4) Cables
-I have no clue how to pick nor what's a fair price for the value

Current plan:
-Used MacBook ($500)
-Decco device ($800)
-Totem Hawks/Sttaf/Arro ($500-$2000)

I realize that there are tons of questions in here, but I appreciate any help with my simple question: what should i buy?!?!

Buy good /popular second hand gear and you can resell later when you want to upgrade for very little loss...maybe a small profit.

How about a Mcintosh MA6500 Integrated and the B&W 805 monitors with stands.
I think you will get plenty of bass and not bother the neighbors...too much.
You can resell this stuff later in a heartbeat.

Not positive about your source.
Look into a Mac and Airport Express to get your music to the amp.
1) Source - A dedicated laptop would create undesirable fan-noise in the living room. Look into a wireless interface, such as the Logitech Squeezebox or you could use the Airport Express.
2) Amp - There's only 4dB difference between 50w and 120w, which is only important if you want to listen to THX reference levels. With the Totem Hawks, you have 88dB sensitivity. With 50w and 120w, you will be able to reach an SPL of 100dB and 104dB, respectively, listening 8 feet away.
3) Speakers - I have no experience with Totem speakers, but if you're going to skip the bass, you may want to get something with a little more bass extension, depending on what you listen to.
4) Cables - They make no or little difference, in my opinion, especially considering cost/value. Buy the most inexpensive set you would feel comfortable using.

I agree with Jeffjarvis that if you aren't sure what you'll keep yet, buy something with good resell value. It would really help come time to upgrade.
check out the last 2 copys of The Absolute Sound,they put together some systems at different price points
Not sure if you got your system already but 50w on Decco is plenty enough. I also live in NYC and I have never had the need to put the volume dial more than 1/4 way and that's on 84 sensitivity speakers. I would recommend getting monitors as they give better mid/treble at your price and adding a sub. If you incorporate subwoofer well, it shouldn't create boomy bass that shake the apt but should be musical and blend in with your main speakers seamlessly. Audioadvisor.com is having a sale on Velodyne SPR 8 for $500 and would recommend them as the company is known to make musical subwoofers.