I'm just glad I have both to choose from. Even though most people say you get better quality for less money with headphones vs speakers, I feel I gotten equal amounts with both of my setups both costing the same. When upgraded my source to the Rega Planet, for example, both my setups benefited greatly. The Rega has let my Infinity's play to their full potential. So I don't really think one way to play audio is better than the other.
And about speakers being the only way to have music as part of the background or environment, I've found I can do the same with headphones very easily. What I do is turn the volume way down. And with high quality headphones, all the details still remain (this of course depends on the quality and characteristics of the used headphone). so for me, turning the volume down on headphones perfectly replicates the feeling of having music as background noise.
Orpheus,
I dissagree that there are as "many" choices to choose from with headphones as there is with speakers. With speakers, the amount of choices to choose from is almost limitless.