Help me detect spyware/keylogger programs?

Nothing there. Why do you think you may have spyware?

"MacScan" is useless.

There's more than one way in which someone who had access to your user account could be spying on you. He could, for example, have the passwords to your online accounts -- all of them. If you haven't already done so, you should change those passwords. Don't use the same password for more than one account, and don't use any that could be guessed.

It's unlikely that you have spyware, but if you do, it wouldn't necessarily be detectable from the information you've provided. Depending on how sophisticated the attack is, it may be practically impossible to detect. If you really suspect this has happened, you should make at least two complete backups of all your data, then erase your hard drive, reinstall OS X, and restore only your documents and settings from one of the backups. Reinstall all third-party software from fresh copies. It will be a big nuisance, but that's what it takes if you really want to be sure.

A highly motivated attacker could have taken extreme measures such as planting a listening device in your home, your car, or your landline phone. That's a longshot, but you can't rule it out.

I might add that if you're concerned about privacy, as you should be, you should remove the photo from your profile (assuming it's really you.) Apple recently added a confusing message to the editing dialog on this site that leads some people to think that they must post a picture of themselves in order to post. That isn't true. Your photo is a bit provocative and won't get you any of the right kind of attention.

A suggestion going along with Linc is that you cpnsider 1Password or a similar tool. This will allow you to set up strong passwords for all of your account which will be maintained in the encrypted database. So all that you need is one password to enter the database for all of the passwords to all of you accounts.

In this way you can protect yourself from prying eyes.

Allan