Thanks for checking with us! Actually, that’s much easier to do in Windows than it is in Mac. So definitely a few things to think about:
* Mac only has one default behavior and no options for lid close behavior. This Apple KB article describes how it works in general: http://support.apple.com/kb/ht3131
* But, Mac doesn’t recognize USB displays for this feature, so if you only have a USB display attached, it doesn’t appear to work: the mac wakes when you hit some keys, but then goes back to sleep again. That might not be a problem for you, if you already have a secondary display attached (on your DVI port).
* If it is a problem, there’s a utility called InsomniaX (http://www.macupdate.com/app/mac/2221…) which can keep the Mac from sleeping with lid closed. It will solve the problem for USB displays, but it has tradeoffs.
* Lastly, DisplayLink’s current Mac drivers are not compatible yet with the upcoming Mac OS 10.7 Lion release. They’ll probably make it in time, but there’s a chance you’ll have to hold off on Lion+DisplayLink until after updated DisplayLink drivers are out.
So that’s what we’d think about. But the DC-125 is otherwise a good match - the screen resolution limit of 1440x900 will actually mean more consistent performance on Mac (higher res gets laggier on Mac than it does on Windows). And it has the extra ports for the external keyboard, mouse, etc. that you’re wanting to use with it.
Hope that helps. Thanks again for asking ahead!