We all have out "baby" rifle...
Mine is my CETME.
I like my CETME for a few reasons.
One of the biggest is I know it well. I sort of lucked out with it, since I have heard some horror stories regarding US receiver CETME's like mine... But I can shoot well with out to 300 (As far as i've tested it), I can snap shoot well with it at close ranges...
I have plenty of mags, which were and still are very inexpensive. It is very reliable (It hasn't coughed yet)- Mil-Surp .308 is pretty cheap to buy. I like it's ergonomics more so than a M1A.
It is .308, which I really prefer if having to choose between butt-kickin rifles. In the enviroment I am in, there is a real possibility that I may be called upon to make a 300-400-500 yard shot, so I like it's range and energy at extended distances.
Of course, if I could afford a HK, I would get one. But my CETME does the job well.
So, that's why I like mine... Just a personal thing I guess. It fits my situation purdy well..
So, "why" is your favorite gun your favorite?