Livezilla's good as long as your comfortable including all the server coding/database needed to run it. There are more than enough external providers as well; just depends where you want the db to reside.

We use comm100.com (Free)
It may not be the best option out there but it's working fine for us. (May be because we done have high requirements)

So I would say it's pretty decent option.

We are using zopim for our live chat its really easy to install and it has a trial version if you want to try its features

Livezilla is the best in terms of features.

Hey,
You can also try livezilla.com, its free & is really good too.

I suggest livezilla

The company I work for uses Activa Live Chat, http://activalive.com. It looks great and functions well.

AliveChat would be another great option.

I'd vote for LivePerson and Kayako's Live Support suite. They've got all the features you would need and are really user-friendly, especially LivePerson.

If you have no budget than livezilla would be for you~

I would recommend zopim.

never heard of zopim, anyone else?

I Would also vote for kayako's Support but Livezilla is also a good option. I am really sorry even I have never heard of Zopim...........

kayako's is a good choice!

We use ProvideSupport. Works well.