This year's theme for Malaysia's National Day is Malaysiaku Gemilang (My Glorious Malaysia). A song with the same name is also chosen for this year's Merdeka (Independence) Celebrations.
It is clearly seen here that it gets its inspiration from the national flower - the hibiscus. And of course, the colours from the national flag - 'Jalur Gemilang'.
This is a new theme, and it has changed from the previous theme which has been used for years - 'Keranamu Malaysia' (Because Of You, Malaysia). As it is a new theme, hence, it was no surprise when many were unaware of the new theme (up to 90% - reported on Aug 8 2007) - a research done by Synovate Malaysia.
But I guess as the National Day approaches, and so many events being planned, more will be aware of it now :)