For my first post I present what I feel is a good balance between noise and performance:
Intel Pentium 4 2400MHz @ 3000MHz | MSI 865PE Neo2-FISR | 1024 MB of Mushkin PC3200 Blue | Asus 8420 (Geforce4 Ti 4200) | Seagate 7200.7 SATA 8MB 80 GB | Samsung SP80 80 GB | Audigy2 | Windows XP Pro
CPU-The firstname.lastname@example.org is cooled by a Zalman AlCu 7000 at the lowest setting.
Fans-The top rear fan is off, it's just there to cover the ugly hole.
The bottom is an old Antec sleeve bearing, attached to a FanMate 1 by threading the wires out through a little notch in the nearest slot cover and then back in.
The chipset fan is obnoxious, but with a third FanMate it's down to an inaudible level. The small heatsink means I can't ditch it totally.
Cooling the drives is an adjustable Enermax, down all the way.
Drives-2 quiet ones, not much to say.
Power Supply- Vantec Ion 400W. Not the last word in silence but for $55 I can't complain. Low, medium and Auto(loudest) settings for both 80mm fans. On medium it's very quiet. I also should mention the excellent connectors, they have an almost soft texture which makes them easy to install/remove while also being secure.
Video card-Cooled by the usual Zalman and clocked way up to Ti 4600 levels.
Case-Enermax. Superb case, almost totally toolless. The drive rails are a godsend, but they are plastic so active cooling is needed as they effectively insulate the drives.