Let's see...
Obvious one is my desktop here. Then there's my tablet, and my laptop - which while I don't use my laptop all that often anymore (seriously I'm surprised it hasn't died yet, knock on wood), it can still connect to the internet. Counting consoles, there's my 3DS, and-- well, I guess there's a PS3 and a PS4 here also. I probably should count the PS4 at the least because it's our netflix player here.
As far as actively use, at least on any sort of regular basis...desktop, tablet, and that's pretty much it. Like I said, the laptop's not used that often anymore, only if the tablet's not available or I need to get/look at something off that hard drive, and I don't personally use the consoles that much for internet-related things. Desktop is for pretty much all my computer-related stuff, tablet is for if I have to be away or if I decide I want to be lazy and go lay down (and yet want to still browse the net or listen to music). Or, more recently, if I want to read something. I kind of accidentally melted part of the Nook I had been using, so I just got the Nook app on my tablet and use that to read the book I've been chipping away at for months now.