For example,take away all my reputation. No one will listen to me. Then give me 300 reputation points,and people will worship me. But did I change? No,just my reputation...

That's an exaggeration.

The idea behind reputation is that it servers as a quick, crude indication of a poster's quality. So far this seems to work, more or less, as people who generally contribute useful content have a high reputation, and those who are rude or break the forum rules (and have been banned before) often have lower reputation. People are obviously free to read a post regardless of the poster's reputation; it's still their call. You can ignore it as well, if you think it's a stupid feature.

The example you gave, for MrBucket, was - in my opinion - an example of the system working as intended. The guy had just registered, already had negative reputation after only 4 or so posts, so there's a possibility that his future posts are also relatively worthless. If you decide to be selective with regards to what posts you read, then that would be a pretty good choice of criteria for what posts to skip.

Is there a list where we can see who has the biggest reputation?

Nope.

is it possible to there be one?

People are going to judge you by your reputation regardless of the reputation system.

Mimmay makes a good point. People will even judge you from your avatar and signature. I know I do sort of. Gives a tiny insight to what sort of person that can be.

dang nabit, didn't even notice the option to enhance somebody's reputation!!
I just thought it goes up with activity:)
That's why I've been stuck at 26!!
Is it my poor manners?
:)

Toni: There's an option on the memberlist search to sort by reputation, but it doesn't seem to work. At least prospectively, though, such a list is possible!

Thanks. Is it going to be fixed?

If it's easy to do, maybe. I'll put it on the ever growing todo list.