In general, we know that USB hubs cause trouble, but surely some out there meet specs and supply 500mA, etc. What hubs, if any, are being used out there successfully with GHI products? I’m running out of USB ports quickly, and would love to use a multi-port hub such as this: http://www.neweggbusiness.com/Product/Product.aspx?Item=N82E16817474012
Let’s see 24 ports and a 4A power supply. That is 167 ma/port. Worse yet is that hanging 24USB devices on one hub will cause a lot of traffic on one single USB port on your PC. If you have items that use any appreciable bandwidth they will likely run very slow as 24 devices are sharing the same connection.
I have an APC 7 port powered hub here on my desk, it works fine. In general stay away form the no-name / bargain USB hubs. Every one of them I have ever owned has been a piece of junk.
28 ports…now that’s just silly… 
I’ve got a couple of these and they work fine. I like the individual switches. I’ve never tried with more than 2-3 devices on at once but in the past 4 months or so that I’ve been using them I haven’t had any power related issues.
I went to the local Microcenter and got a cheapass $15 hub.
http://www.microcenter.com/product/360454/7-Port_USB_20_Hub_with_Power_Adapter
It’s lame and has a very obnoxious bright blue LED light, but it gets the job done. Note that I’m only powering the FEZ with it, nothing else plugged in except the occasional flash stick to transfer some files.
I’m also running the same hub as @ ianlee74 from ThinkGeek and its worked well for me thus far. The individual switches are what sold me on the hub as I like turning devices off when I’m not using them or reconfiguring them.