Interesting... I do agree with what a lot of you guys and gals are saying that fillers do create some annoyance where it is unrelated on all levels and does not co aside with the storyline. But I believe that there are some fillers out there do contribute in some way where it may not be in relation to the storyline but may help understand certain things, such as characters explains them better so we get to know them better for future ep's or other relevant things that might help contribute later on.
One thing I do like is what Full Metal Panic did with Fumoffu! (btw if I could cosplay one character from there it would be Bunta Kun!! xD) Its after the anime had ended but it was random every episode and it wasn't dragging the core story out so it was enjoyable to watch knowing that there was something different was going to happen the next ep. Stuff like that I like, would be good if more animes did this it would give the creators a chance to go wild in a sense and do things they may have wanted but couldn't do for the main storyline.