Even Light for Hot Shoe Flash

Lately I have been unhappy with the results of my flash work. Sometimes I am getting uneven light on my subjects (for example, sometimes when I bounce my subjects are noticeably top lit). I am shooting with a 580EX II mounted on the hot shoe of a Canon 40D.

I am looking for a sort of "go to" diffusor to use when I encounter flash issues, such as bad bouncing conditions, uneven flash results, etc.

Can anyone recommend their favorite diffusor to use on a hot shoe flash that would help even out flash light? On camera softbox, omnibounce, etc -anything specifically that in your experience creates even light for a hot shoe flash? Any and all tips on this subject will be immensely appreciated.

Additionally, if you recommend a great book on flash work, please share.

Thank you all!!

PS: I primarily shoot weddings

I can recommend a couple of on-line resouces that are invaluable:

For general flash usage, look here.

For wedding-oriented flash usage, look here.

Hope these help.

I have a Lumiquest Pocket bouncer that seems to work pretty well when I can't bounce off ceilings (that are too high, non existent, or "colored").

In addtion to what roger provided, another site that is pretty good: http://strobist.blogsp​ot.com/

this is what I use

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE