I recently bought Half Life 2, today in fact. My friends have been very praising of it graphically and story-wise, and from the look of the screenshots it does seem very good. But, I have also heard nasty stories about installation and CD-Keys and all that, in that once it's installed on one computer it can't be installed and played on another.

I was wondering if there was any truth in these stories, because if there is I shall refrain from installing until I update my computer (soon). Also other general information about it would be welcome too (tips, opinions etc.).