Gentoo is doing some cool things, and its best ideas are not surprisingly being adopted by Debian.
However, I'd just like to point out that the proposed "advantage" of Gentoo in getting a "highly optimized system" is more an urban legend than anything. A product of the subconscious of those who wait dozens of hours for a system to _install_ and want to believe it was worth the wait.
So far I haven't seen a single independent test that shows any performance advantage to the source-compile-everything approach of Gentoo. To the contrary, independent tests have shown that it actually fares worse than Mandrake or Debian.
-Roberto
P.S.: I like Gentoo. Just trying to dispell a myth.