I think I came to the K701 with an approach similar to the one you had: to get a high potential headphone that may benefit from dedicated amplification down the road.
I am enjoying my K701 without amplification. Here is my limited experience: I bought the K701 and the Headroom Total Bithead portable amp ($149) for use with my Ipod (classic, 6th generation) and my laptop computer (Fujitsu P7010). As a headphone amplifier, the Total Bithead made no difference to me. The only difference it made was when I used it as a USB digital/analog converter (i.e. sound card) out of my laptop: I heard a few more, very subtle, details (pleasant to have but not necessarily worth, for me, my $149, i.e. definitely not a night & day experience).
The one area where the K701 leaves me wanting is for music that has few acoustical instruments, with a sizable amount of (wanted) bass and when I listen at low volumes. When these 3 conditions are met, I am not very satisfied. This is an area that will motivate me to research the benefits of quality amplification. When these 3 conditions are not met I am a happy customer. The K701 really revealz the complexity of my recordings in a manner such that I find myself listening to my music much more now. It is, for me, similar to to switching from an OK to a very good wine.
The next thing I will write, and for me it is what makes or "breaks" the K701 experience, is that they must go through at least 100 hours of "burn in" before being thoroughly enjoyable. I was very disappointed when I listened to my K701 right of the box. They did not sound "right." (You can see my the extent of my audiophile experience by the complexity of my description
). I followed the advice I read and let them play random music in a drawer by themselves at moderate volume for about 100 hours. What a positive difference it made!
Lastly, I rip all my music to the highest definition available (in iTunes: WAV, 48Khz, 16 bit). I did not make comparisons with my K701 between high and low definition formats but I did with a previous Bose headphone and the difference was quite significant.
Hope this helps.