How MS can get me back into XBL
First, scrap that Gold BS, you aren't fooling people, at least not me and I'm sure many others. If you're going to keep Gold around make it more like PS+ where people get actual benefits for paying and not just access to things that have been free on the PC and everywhere else for like ever.
Second, integrate XBL into Windows so that any indie devs can contribute to your service. If Katawa Shoujo (NSFW) or Octodad (Funny and SWF) want to give me achievements they shouldn't have to go through so many damned hoops. You can segregate the console from the PC, and even hide Adult content on people's profile that is on PC, but it should still be something that should be integrated with Windows. When people earn Steam Achievements it should contribute to XBL, when a small dev isn't on Steam they should be able to contribute to XBL too.
Third, re-brand the service. Xbox is the console, but the service should be universal among your devices and software (Desktop Windows, WinPhone, Xbox) and the name Xbox doesn't accurately reflect that at all. Something simple like MS Games Live conveys the fact that it is game centric while not annoying people that don't like the Xbox or confusing people that never heard of the Xbox. Basically, the same thing you did for the Zune has to be done for XBL.
Fourth, You should have a minimum PC spec so that small games from the XB Store can be played on the PC as well. Sony is doing it (PS Mobile/PS One Classics/PS Minis) so why aren't you? In fact all indicators point to Sony expanding it even farther thanks to their Gaikai purchase yet you aren't even in the conversation when it comes to cross-compatibility. You're freaking Microsoft for crying out loud, you are one of the kings of software so why on Earth are you letting a hardware suit like Sony eat your lunch when it comes to things like this? And that doesn't even count the other hardware suit eating your lunch too, Apple. Their software is moving between iPhone and iPad and the Apple Game Center is also on the Mac. Come the hell on, since when has Apple been about the games? They aren't even trying and are ahead of you on that front.
I made an XBL account years ago back when I (briefly) had an Xbox but never used it except to buy something on PC for the crappy GFWL service. That shouldn't have been the case and you should be ashamed Microsoft. Windows 8 is coming out as is the Next Xbox and your new Phone OS. Don't botch it up a third time.
UPDATE: Reworded some mildly inflammatory language from the first sentence.