If you want to reach the top of the lifetime sales charts, having a hyped product is always worth it: Halo 3 or Assasin's Creed are there to attest that the first weeks are important in building best seller contestants.
Althought, what's gonna make you go further up is becoming a long-term seller (even with a slow start). Reaching the target market you're aiming at is less current but when it happens, can be worth it... you kinda become a "classic", a product picked through time because you're in the top 3 or 5 games people will buy or offered on the platform even a few month or years after you've been out at retail.

Mario kart or New Super mario on DS are amazing long and best sellers (because they even stay in top 10 sellers in lot of countries). and I’m proud and surprised to see that Daxter on PSP is one of those products that manages to sell constantly through time, making the US December sells the biggest month ever since the game was launched almost two years ago (and this is without including bundles sales), making Daxter one of the top sellers of the console... For what i can tell, we sold more than new products like Nights (Wii), Half-Life 2 (PS3) or TimeShift (PS3). (i took those three games because their numbers are available and given by the NPD group).

That's an amazing reward for the team to know that the game pleased so many people and brought them some fun! That's why I’m working on this industry, and I’m happy to know that one of my goals has been achieved.