Generating complex passwords is an increasingly important way to protect your private info and using easy-to-remember personal passwords is not always a good idea.
X-Lizard Password Generator is a software program to generate random passwords containing a varied set of characters, including lowercase and uppercase letters as well as numerals. Afterwards, you can simply copy the password to the clipboard or save it to file.
You can define, in characters, exactly how long you want the password to be and whether you want it to contain special characters. You can go online to download a few more skins, although this is hardly the kind of application that you really care how it looks so I don't see much point in that.
If you need a highly complex password that's pretty much unbreakable, X-Lizard password generator does it well.