if it really was you who put the password the best piece of hardware you can use right now is your brain
relax and try to recreate the whole scenario, time, place, mindset of when you were leaning on the bitcoin client, then put your hands on the keyboard, focus and start trying
hopefully the password will emerge
source: my own experience, I have set up a password on a 50 btc worth wallet. This is how it happened:
It was late night in a hostel, the only computer avaiable, not only a public a PC but I had to use standing up, and, to increase the anxiety level, I was drinking beer. Put the password and shutdown the PC. Then I left the place I was for three days, here is where I needed the password and: WTF?! Wrong password! Don't panic. At this time the password only existed on my brain, then just said to myself I was going to remeber. I did exactly as I told you above. Took me one day to go back to the place I had set up the password. And two more days acting like "12:01" movie to finally extract it from my mind. The pass was a 12 chars long phrase.
Hope this inspires you.

I know this is probably way out there, but I just wanted to say thanks for this.
I recently was having trouble getting into my LTC wallet and even emailed myself clues as to what the password was. But I could NOT get in. I started googling solutions and came across this thread. I read this post and I admit sorta rolled my eyes. But figured "why not....what have I got to lose". Turns out I ended up typing part of my anniversary wrong (even confirmed the date with the wife!

) and it was still wrong. Finally I said, "I wonder if I typed my daughters BD instead?" which happens to be the same numbers, just different format. VIOLA.
So thanks for this! If you accept LTC I'd love to send a few your way!

Also, for anyone else who might be in the same predicament and hopefully save you some time and frustration. I did quite a bit of googling and I'd guess probably 80% of the password issues people were having were from mistyping it in twice. I know it seems like it would be difficult to do, but it's way more common than I would have thought.