The first thing you must understand if you want to keep on watching is that Bleach is a long running anime (225 anime episodes and counting) of which there are very few now in japan,the other two big series being One Piece and Naruto.When a series runs as long as Bleach the chances are it will outpace it's source material ie. the manga .This is when filler comes in to play.
So far there have been two major fiiler arcs in the Bleach anime,the first one is the Bount arc which takes place between the Soul society arc and the Arrancar arc.The second filler takes place between the Hueco Mundo arc and concerns a new captain joining squad three.
Of these two filler arcs ,the Bount arc in my opinion is the better one.While filler as a rule is not meant to advance the overall story or characters in the series that does not mean you can't enjoy them as stand alone stories in their own right.
Some people in this thread have mentioned that the overall quality of the latter episodes has declined since I don't know how they viewed these episodes,I can only speak for myself.I have watched all 225 episodes at least twice ,sometimes four or five times all on my high-end dell pc from streaming fansub websites and I can tell you that you truly cannot make a comparision between watching an episode on a small screen on a pc from a fansub website(if you try to expand the picture to cover the whole screen it usually degrades) and watching the properly made dvd on a full screen tv.
As for the big question?,should you keep watching?.Well as for that I can only say this .First ,why did you start to watch Bleach in the first place ?,answer that and you're well on your way to deciding to continue to watch it.Secondly ,having watched all the episodes,movies and ova's and read the manga,I can say this their is more good than bad in the Bleach universe but if you do decide to keep watching you are surely in for the long haul as at the rate both the manga and anime are progressing Bleach will most likely past the 400 episode mark.
Just so you know,I will be watching Bleach till the end because when you invested this much time and intrest in a show ,to stop watching before the end really does mean you've wasted all that time and effort for nothing without seeing how it finally plays out.