I do play Borderlands. But I'm at the mercy of the people I play it with. My wife doesn't really want to play more than the 3 or so hours we already put into it. My Bro-in-laws-Bro that I played 6 or so hours with moved away. My zombie friend (zombriend?) and I play it when we can't get 2 other people to join us for L4D, which we've been able to do recently. I'd be happy to play 4 player BLs, but the other two people don't have level 15 characters, so that would be awkward.
I've really wanted to play BLs some more... zombriend and I will have to set up a private date for some 1-on-1 splitscreening.
RE:Halo 4
Like C3PX, I have to say I'm more interested in Halo 4 then I ever was for Reach. I ended up getting Reach for Christmas last year, which was probably 6 months earlier than I was planning to get it. I get very few games the week they're released, but Halo is a frequent exception. Reach was an exception to my Halo exception.
It will be interesting to see what 343 does with it and how it compares to the Bungie releases. I have to say I'm not sure if Bungie will fare better without Halo than Halo will without Bungie.
Anyone who beat Halo 3 on legendary or read Ghosts of Onyx has been waiting for an official Halo 4 announcement for a while. So I don't think it's a terribly big surprise. I do hope, however, that the story of the Flood and the Covenant is over. Halo 3 was advertised as your chance to "Finish the Fight". I'd like to see a new direction for Halo 4. Inasmuch as they've advertised it as a "new trilogy" I imagine they have a new direction for it. Hopefully it's a good one.