And just to confuse the issue even more, all my Arduino stuff connects fine when connected to a powered hub but an AVR Dragon doesn't, nor does my digital camera. Some items are finicky.
I've done some further experiments and my digital camera won't even connect unless I unplug the USB hub.
I had a cheapo USB hub in the past and got rid of it because of similar problems, but it seems all USB hubs suffer the same problem. My hunch is that it is a software/driver issue.