While prefixing your "favorite" passwords helps, it's still exploitable. If someone can see your password in the "clear" they'll be able to tell if you're using a strategy like this. I have too many accounts---and what happens when you have collisions? Did I use "f" for facebook and flickr or "fa" and "fl" for them? I'd rather be consistent with a tool than with a meatspace algorithm: http://keepass.info/ is probably more reliable and secure in the long run. I've long since abandoned trying to keep authentication data in my personal meatspace and I don't recommend meatspace methods anymore /except/ for securing your authentication database.
