Version 3 offers a completely overhauled interface, tabbed chatting, enhanced messaging functionality, improved file transfers, and a new Instant Lookup feature.

Trillian has rightful title as king of all chat clients. It is a single solution for handling all your chat traffic.

The program offers simultaneous access to the fab-five chat clients:
1. Yahoo Messenger
2. MSN Messenger
3. ICQ
4. mIRC
5. AIM

Trillian acts as a hub for all your chat traffic by importing your passwords, buddy lists, and client preferences into its own interface, installation and setup are simple, and the included features are awesome.
You can also check supported e-mail accounts with one click and view detailed event logs.
Plus, each supported chat client has options such as video and voice messaging and file transfers. Trillian also offers skin support.
Trillian Basic version offers great feature and Pro Version offers even more.

Pros:
Just a single client for chatting on different networks.
Interface is very easy to use.
Can be configured for different users.

Cons:
Only Pro version has Plugin support.
No support for Mac & Linux users.
Basic version doesnt allow video chat.
Takes a good while to load up.