For chat: Pidgin. Being open source, their's no ads and you're not selling your soul to use it. It works well, and with virtually any protocol (facebook, google, AIM, ...)
For Twitter/Facebook/Digg/RSS/Etc. feeds: MahTweets. It is open source, using Microsoft's new Open Source license. Its interface is clean, it is customizable, and it is a CLIENT. it is not something you need to open your browser to use.
I've been looking for a pair of applications like this for a while. I hope others find this useful.