Well I've been using Trillian for IM for years and found it to be a good application. It has a few foibles (http://www.thefreedictionary.com/foibles), but does the job I want.
I find it especially useful for checking connections to various parts of the net.

Unfortunately Trillian has some rather annoying issues with Windows 7 so it's time for a change.
Now I really don't want to use 12 different IM programs so an all in one solution is called for. Also zero advertising, if at all possible.

So what is recommended?
I'm open to any suggestions.

Im still using Trillian but my team is moving to Digsby which I hear good things about:

Digsby = IM + Email + Social Networks (http://www.digsby.com/)

Although it was recommended, I just found this":

Digsby Joins The Dark Side, Uses Your PC To Make Money | Lifehacker Australia (http://www.lifehacker.com.au/2009/08/digsby-joins-the-dark-side-uses-your-pc-to-make-money/)

So maybe not.

Well after several failed attempts, I have stuck with Trillian.
The all new Trillian Astra is a really awesome application. - Link: http://www.trillian.im/

Not only does it work with the major IM players, but integrates with Skype as well as Twitter, Facebook and MySpace.

Very good indeed.
Best of all it works well with Windows 7 ;)