Proper Multi-PC setup?

OK, so this might be a little silly to ask, but after reading a lot of forums lately I'm beginning to think that I've got the HTPC setup in my house wrong.  I've got a desktop PC upstairs in my bedroom, an Acer Revo nettop downstairs on our main TV, a 50" plasma, plus a NAS drive on the network for our media.  The Acer gets used probably 80-90% of the time and is the one we schedule all our recordings on.  The desktop is on a dual monitor setup with a 32" Toshiba flatscreen as the TV we watch WMC on, and a regular Acer monitor for normal computing.  Currently I have both of these setup essentially as their own standalone HTPC as opposed to one HTPC plus an extender.  My question is, is it better to have one as an extender?  What would the benefits of this be?  One of the reasons this question popped up was because, as I mentioned before, we setup our recordings on the Acer downstairs but we want to watch those upstairs as well and sometimes we want to watch a recording while it's still being recorded.  I've set up Recorded TV Manager to move the recordings to the NAS drive so the upstairs PC could access them, but they generally don't move for a couple of hours, and especially not while they're currently recording.  If my setup was one PC plus an extender would this help us more easily watch our recordings upstairs, or is there another way to do this that I'm missing?  Also, would I only have to setup one computer the way I want with all those settings being passed on to the extenders?

I know this is probably basic but I really didn't give it much thought until recently and haven't had time to research a nice comprehensive guide.  Thanks as always for any response!