Only when it actually makes sense for some practical reason. In most cases people confuse artistry and the faster evolution of exclusives due to the fact that the developer is programming for one console and not two or more as some inherrant benefit of exclusivity when much of the advantage thats seen by people is just talented artistry.
What most people want are really good games. The most popular titles on the Xbox 360/PS3 are multiplatform and it shows how little it really matters overall whether a game is exclusive to the point where one of these systems is excluded. Nintendo on the other hand really do take advantage of the uniqueness of the Wii to great effect so only really in that case do exclusives actually make sense because they are simply not possible on the Xbox 360 or PS3.
I endorse exclusivity for the PC and Wii because they actually do make sense given whatever ambition developers might hold and both platforms are actually unique with unique strengths and weaknesses. However the only reason not to release a PS3 version or an Xbox 360 version in 95% of cases for the DX9 consoles is just because a console maker is paying the bills.
Tease.
