Mobile design - so many choices

I want to make my first mobile-friendly website and I’m seeing lots of choices: server-side detection of user-agent strings; client-side “media type” detection in the CSS; letting the user decide explicitly; also choices about whether to use HTML -vs- XML, or even specialized stuff like WML/WAP.

Since I only care about current mainstream Droid phones and iPhones and I’m just beginning with this stuff what’s a good way to start off?

Thanks in advance.

Developing alternate sites is a big job, so only worth it if it’s a big site and there’s a lot of $$$ involved. Browser sniffing is not well regarded these days. Using CSS3 media queries is a nice option for iPhone (but I’m not sure about Droid).

There is a fairly recent argument that the best approach is to make a clean, simple site with basic styling, and feed special media styles to devices that can handle them, like iPhone and modern desktop browsers. It’s an interesting argument.

That depends on what mobile applications you plan on designing