Look for a quiet 48-port (or stackable 24-port) gigabit switch

GOOD LUCK

Well I think I might have found one (HP Procurve 1800):
http://www.procurve.com/products/switches/HP_ProCurve_S...

Just trying to find out if they can be stacked.

I doubt they are stackable since they are web-managed only. I know the Cisco 3750 series is stackable and man is it great. I have several 8 switch stacks that are working wonderfully. Nice to only have to program and remember one IP address.

Netgear have a bunch of web-managed stackable switches. Unfortunately they all have fans, even their 24-port models.

We're probably going to go with the Procurve 1800 even if they aren't stackable as they've got really good reviews (somewhere in the bullet proof range apparently) and we only need the 48 ports for if we expand again, at which point we could simply purchase a 48-port switch. Just would have been nice to only have to buy another 24-port switch.

Well I think I've found one. The Procurve 2510 Series:
http://www.procurve.com/products/switches/ProCurve_Swit...

It's a fanless, stackable, managed switch, And it's actually cheaper than the 1800 series.

Don't quite understand the difference between it being managed and the 1800 series being web-managed. Does this mean, for instance, that the 2510 series will be more difficult to manage?

I specified and installed a 2510-24 and am very pleased. It has 10/100 to the desktops, and a 10/10/1000 gigabit uplink to our main switch. Actual power consumption (thus actual heat) is roughly half the spec, and it is indeed fanless, and indeed has a "forever" warranty: http://www.obviously.com/tech_tips/Switch_Power_Consump...
The 2510 appears to be both manageable via a web page, and via SNMP.

Didn't cotton onto it when I posted my last post but the 2510 series doesn't include a fanless gigabit model. We actually went with the 1800-24G (J9028B) in the end which is working out great.