Future-compatible sounds good. How about backward-compatibility with old browsers, such as Netscape 4?
Few things block web developing as much as Netscape 4 and the reasons for still using it disappear for each day, as do the reasons for developing for it — its 'rebel' attitude is long gone, the "average web user" don't use it and on-line banks do not longer require it but even start abandoning it.
That said, sites coded with web standards don't block older browsers from viewing the pages. They just don't get much of the pretty looks anymore. Remember, accessibility is key and to require a user to download another browser just isn't common pratice in anymore.