Please don't laugh at my questions; I am a complete beginner and I like mixers (I guess being an engineer I like lots of knobs :) )

I was wondering if there is any use for a simple mixer in setting up a home audio system.

The main reason I am asking this is that I want to hook up my guitar to my home audio system and have my practice CDs play in parallel. I also want to connect a mic to the system.

In addition to this I want to connect receivers, DVD players, etc to my audio amp which doesn't have as many inputs as I would need.

So, is this a reasonable situation where a simple mixer might be useful? If so, would you suggest some mixers for a beginner?

Thanks.