Do Macs care which USB socket you plug devices into?

Not really, or at least not to the same level that Windows does.

It's up to the driver; here are some rules for devices supported by default.

• It doesn't matter for disks.
• It doesn't matter for HID devices (mouse/keyboard).
• It does matter for audio interfaces. You won't have to “reinstall”, but it will be considered a different device so you'll have to choose it again from the list of audio devices.

There is something else to keep in mind with the Apple laptops. For some reason there is slightly more power that comes out of the USB port that is closer to the power adapter on your machine. You can tell the difference because trying to charge an iPad in the wrong USB port will cause it to take MUCH longer. http://www.wired.com/gadgetlab/2008/05/the-macbook-all/

However, as far as the software goes - there mac is very forgiving if you plug a printer (for example) in to one USB port one day, and another USB port another day. You don't have to re-install (or anything similar)

This apple help document is probably better worded than my reply is: http://support.apple.com/kb/HT4049