One of the earliest memories I have working at Microsoft was the wave of products released in the first six months or so that I worked there. There was Windows 7, of course, but also Visual Studio 2010, and all of the associated technologies that DevDiv produced (where I worked). My team was mostly concerned with making the forums on MSDN suck less.
The next big wave of stuff came in 2012, after I left, and included Windows 8, Windows Phone 8, Surface and Visual Studio 2012, which had to be released together (largely because of the politics and influence of Sinofsky, the way I understood it). That was a pretty exciting wave of stuff. This year we've got Windows 8.1, which has some nice refinements, and VS2013 and updated frameworks in the dev space.
What's interesting this year isn't that there's any particular earth-shattering update, but the pace of evolution with development products is really, really fast compared to what it used to be. The tools are so freaking good now. The whole stack is getting down into the roots of what the Web is (HTTP), and they're going a long way toward decoupling from what the core of what ASP.NET is (System.Web). The reason that's so cool is that this stuff isn't just the domain of a Web server anymore... you can really run it anywhere. As my boss and I were discussing today, that's kind of a future state sort of thing, but it's still exciting.
Heads down development for me is largely the domain of my personal sites and projects, not my day job (it's mostly issues of architecture, compliance, code reviews, etc.), but it's still really energizing to see all of this new stuff coming down the pipe. I'm anxious to learn more about it, and really dig in and do stuff with it. It's like my experiment with Azure in May... I didn't have to do it, but I wanted to. It keeps me sharp.
Not everyone in the field of software development is like that, unfortunately. That's a shame, because the tools and products have become so incredibly useful. Our experience isn't the biggest roadblock to creating awesomesauce anymore.