I've got a Scythe Ninja 2 in this machine,
you can run it without a fan on it if your CPU is relatively low power. I've also fitted an OCZ Vendetta II before, that's quite good. I'm just about to take delivery of an Akasa AK 920-2, which is getting good reviews despite being fairly cheap, so I'll let you know how that turns out.

What processor have you got?
( Moon Girl Technologies horrendous beanbag, Sun 31 May 2009, 21:53, archived)

Core Duo something or other, dunno, it's written on the box
I really need SILENT cooling for it for home recording purposes
( Gilgamesh gazed in wonder as Frampton came alive, Sun 31 May 2009, 21:55, archived)

A Scythe Ninja ought to be able to cope with a Core 2 Duo,
you can usually set the BIOS up to run the fan at variable speed as well. I'm assuming the PC case has fans in it as well?
( Moon Girl Technologies horrendous beanbag, Sun 31 May 2009, 21:58, archived)

yup, switched off that Q-fan crapola, case is old and stuffed with hard drives so that needs replacing too
I'll go and shovel some more money into Micro Direct next week
( Gilgamesh gazed in wonder as Frampton came alive, Sun 31 May 2009, 22:00, archived)

You'll want a case that'll take 120mm fans all round,
the bigger the fan, the slower it needs to spin, so 120mm is now the quiet computing standard. You can get gaming cases with 240mm fans in the side, but that's just daft.

Scythe and Noctua do the best fans, you're looking at £12-14 each.
( Moon Girl Technologies horrendous beanbag, Sun 31 May 2009, 22:03, archived)