Thank you for the suggestions all
Is an amplifier required or recommended to drive any of those choices?
Also, which would you say is the most portable other than the Sennheiser HD-25 as I would be taking them to the office and back on a daily basis.
Perhaps I wasn't clear when I said "I need something natural-sounding". What I meant was that from what I understood about what natural-sounding means, I think this would be the sound I prefer.
I completely agree about it being hard to find what I want without being able to test the options first. Especially since this is going to be my first decent pair of headphones!