If you play piano you should find a tuner who does something better than equal temperament. When you accept that changing keys will change the tone of the song you can get a lot better music. You don't need to go to just temperament (and since you still need octave stretch it wouldn't be ideal anyway - though if you can live with playing music in exactly one key it is nice).

I tuned my piano to EBVTIII and I like it. (well I tuned 3 notes and then got my son interested and he tuned the rest). It isn't as hard to tune a piano as professionals make it out. However it takes me about 5x as long so if you can find a good tuner I'd call it worth it.