For current pricing check out this page on the cPanel site.
http://cpanel.net/dist.cgi

I would not want to pay that every year for Cpanel but if you were a hosting company it would be good to have because it is so widely used and it is a known standard.

I will agree with you on this one, if your just running personal websites. I do not see the point of paying all that money for cPanel. Depending on who you co-locate your server with you could rent cPanel for $25+ per month. But thats still $300 per year. And as I said before Webmin is free and it can do any thing cPanel can do plus some.

I think a lot of hosts use it though because it is well known and people want to see that they are using a well known control panel like that on there servers and people most likely have used it before then on another host or somewere,

I really like the ease of cPanel, and the fact that there are custom skins available for it.

I do agree though - cPanel is so dominant, it's become..."implied" with everything. Webmin (which I've never heard of) seems like a decent program, but just doesn't have the flexibility, look, or features that I want.

We have more than 10 servers at the moment and we use ISPConfig. Great linux control panel, free and has great forum support.