Mother Boards and Cases

[walkswithdog]

I am new to the idea of building an OS. Can anyone tell me their opinion of IWills motherboards and the HTX case (300 watt power supply)?

Lastly what is the physical relationship between a heatsink, power supply and the case?

Thanks in advance for any help.

Jim, Salem, Oregon.

PS: I am looking toward a budget of under $800.00, without the monitor, keyboard, mouse and speakers.