I'm just gonna keep saying this in the hope that it will sink in....

Multimedia is more of a strain on your system than other non-leisure applications. Balancing your checkbook isn't going to need a powerful computer. Playing video games will. Watching HD-DVDs or Blu-Ray discs is going to need a more advanced system than running Word or Excel. Your non-leisure machine is really the one that should be cheaper.

Playing online games is going to cost you money one way or another. You need to pay for the internet connection anyway, and you'll need to pay a subscription fee in addition. Different companies go about this in different ways. Very rare is the MMORPG that is free. Less rare is the FPS server that is free. Regardless, one way or another, you're going to have to pay money for it.

Backwards compatibility does not cripple a system EXCEPT for in the case of Windows, but only because Windows 9x was so hideously made that you could make it crash by blowing on it. A slight update to a system isn't like PS to PS2, it's like WinXP with SP1 to WinXP with SP2.