A must read presentation by @bryanrieger. There is a premise here that says that there are large numbers (as in, mind blowingly large) of people that can and are accessing the web with less capable devices. Bryan presents a way to serve content to them, and outlines techniques to "build up" an experience for full function devices, thus having a great experience for all visitors.
The technical description and issues around different devices make for an excellent presentation, as it really lays out the issues today.
However, I honestly don't think there are enough tools in place to help LARGE websites do this. I am least interested in landing pages or beautiful sites that are primarily designed and implemented as hand crafted pages by top designer / developers. I have NEVER been interested in those types of sites: they end up being static sites that don't reach a lot of people. That is why I am so interested in the democratization of hosting / design by platform tools like WordPress and Drupal.
Mike R agrees with my point of view - this type of design is just not possible on a mass scale given the tools we have today.
For now, I think that tools like Mobify (where I am an advisor) are the best solution to address a wide variety of devices. The build for desktop, then provide optimized, automated views / designs for mobile is the best mix of pragmatism and experience delivery.
For "best experience" type of design, today we are reaching for native apps on each platform.
Frameworks like Nitobi's PhoneGap provide a bit of a bridge - using web design tools / technologies, but taking advantage of native device functionality.
HTML5 is a piece of the puzzle, and what's possible there will improve as the operating system / web browsers available on mobile devices get upgraded / improve over time, but there is still a vast gulf between software-oriented smartphone systems (iOS, Android, WinPhone7) and feature phones that will follow a 3 year handset upgrade cycle.
How do you approach web design & development in an age where mobile and apps are increasingly important? I think data design, social objects, and services design are the most important. You build with an API strategy in mind, even when you are "only" building a website.