My favorite tech stack today is CouchDB (Cloudant), DropWizard (middle-tier Java framework), Knockout + JQuery (yes, I know, I should look at AngularJS), and Bootstrap 3 (for responsive design).
I like it because DropWizard is pretty lightweight, while still giving me a good REST framework. Cloudant gives me JSON over HTTP calls making it easy to pass these representations out to clients. Knockout + JQuery isn't the darling of the community right now, but it fits the way I think about the web page. And Bootstrap really is like legos for web developers.
Next up: I'm taking an iOS class at Smart Factory.
Update: As I was writing this, a friend of mine sent me this Google Trend of Angular vs. Knockout. Not just because of this, but I am convinced I'll spend the time to learn Angular for my next web app.
What's your favorite tech stack?