Instant Messenger Software Recommendations ?

Hey Guys,

Can anyone recommend a good piece of software that lets me combine all the IM accounts (ie Yahoo, AIM, MSN, Skype) into one application.

Would prefer software rather than web based.

Cheers

David

Trillian is what I along with a tonne of people I know use - http://www.ceruleanstudios.com/

Although it doesn't support skype and a couple of others.