Car Stereo Installation

I`d like to see what people have done here. When I bought my 67 convertible it had a multi-disc player/radio in the trunk with a wired remote. Cool system but much more than what I really wanted. On my other car I sent the original AM out to a company that gutted it and installed a 4 channel amplifier with 45 watts per channel, AM/FM, and aux. inputs for MP3`s etc.