Should I be using Time Machine?

Hi, as far as I know Time Machine backs up my entire computer. My question is can I pick and choose what I want to restore or is it "all or nothing"? My current mid 2012 MacBook Pro is buggy, glitchy and has a million files on it that I have no idea what they are. The last thing I want is to buy a brand new computer, restore Time machine back-up and turn my new device into the mountain of garbage that is my old device! The only things I want to transfer over are photos, iTunes library and some select documents and files. In this situation is it better for me to just copy those items to an external hard drive and forget using Time Machine all together?