The last time I assembled a Desktop, Antec cases were the cat's meow for quietness. However, I haven't been able to use that machine for many years due to repurposing in the household.

While they die a quicker death, I'm partial to laptops now for recording specifically for lack of noise. Incredibly quiet compared to even the best spec'ed desktop.

As for repairs, laptop repairs aren't that much more difficult than desktops (I've been putting things in and out of desktop cases since about 1988 or so), as they have to keep things even more modular than desktops - for example, you won't find that many stray cables wending their way through the innards of a laptop, blocking airflow and whatnot. They are simple enough to swap parts that many laptop repairs have been given over to UPS. Yes, that UPS. Read about it in 'The World is Flat' by Thomas Friedman.

If you want to spec your own quiet desktop, there's enough resources online to assemble a relatively quiet desktop machine. I used this site http://www.silentpcreview.com/ the last time I built and they are still cranking out the reviews and information.