Computer parts need fans to moved heat out of the case. My computer have 10 fans and I do not think 1 less fan will help very much. If you want a computer with no fan then you need a computer with components that does not produce too much heat.
look at this cool pc:
<A HREF="http://www.stealthcomputer.com/littlepc_fanless.htm" target="_new">http://www.stealthcomputer.com/littlepc_fanless.htm</A>
Bladerunner has done some awesome water cooling projects.
<A HREF="http://forumz.tomshardware.com//modules.php?name=Forums&file=viewforum&f=7" target="_new">Check out the new Case Mod and PSU section of the THGC</A>