A title screen should set the tone for the rest of the game, whatever that may be.
Morrowind had a very effective one, with the hearbeat sound accompanying the song playing. The initial of each house at the corners of the imperial logo.
Civilization 4 had a great main menu. Showing the earth spinning (EDIT: now that I look at it, it doesn't spin, only the clouds do) while having a great track playing in the background (fun fact: the song was the first video game composition to win a grammy).