My first upgrade was graphics card, wen't from R9800@pro to GF6800GT with gainwards massive two slot two fan thing that was damn loud even with fans @50% in expertool. I ran it sometime with this setting, but it's massiveness also forced me to upgrade mobo (covered one of SATA connectors) and case (too cramped, GF molex left just enough space for ATA cable between it and HDD). I eventually went with antec superlanboy, smaller than my olg 1000AMG, but more wisely used space that didn't have same propblems. Not the most silent one in market by it's lightness was attractive, it also offered 120mm fanmounts.
My first thing then was to replace that gainwards cooler. First I considered NV5, but it would had to mod cards backplate (as it was time before ver2 that offered ultra compatible backplate), so I wen't with zalman.
^^ my gainward mounted with zalman VF700-CU
I also changed my stock CPU cooler with Zalman CNPS7000-alcu. Next thing was to swap my old antec psu. Considered passive solutions first, but was worried of their heat output, and as not many 400W+ models were available here I wen't with Nexus. Sleeving that psu wasn't as easy as I though (my first sleeving project) but eventually came ok. I also changed superlanboys 120mm fans with nexus fans. Tryed to find 120mm panaflos from finland, but with no luck.
With all this work I had cut down noise to half of what it used to be, but all fans we're on 12V (except CPU) so I could do better. And las but not least I bought fan controller that really made my rig quiet, and now I can sleep easily with it on.
^^ Akasa fan controller I now use
Eventually noise was reduced to low humm, with no high pitched sounds. So I can be quite satisfied with it.
Some more pics:
^^ Nothing fancy at front
^^ I could do better with cabeling, but it's good enough for me. Notice that old Maxtor ATA drive, it's currently unplugged as waits replacement, it was one of loudest components in my rig. Three others are 2x samsung 160GB sata and one seagate 300GB sata.
^^ Obligatory night shot
^^ Tools I used in this project, notice the "custom-bended-paperclip"-molex remover on leftmost
, I had to flattten it a bit so it would fit into ATX power molex, but it worked like a charm.