The E17 is more than capable of driving the 250 Ohm version. The 250 Ohm version is in no way bass-light - its bass is just more neutral/flat, whereas the 80 Ohm version has mid-bass hump. Since the E17 has that nice bass boost feature, you will be able to achieve a very similar sound to the 80 Ohm version, if you wish. The 250 Ohm version is superior in terms of sound quality and neutrality, so if you have a source that can drive it, there is no reason to go for the 80 Ohm version. Naturally, this is my own opinion - I have auditioned both and chose the 250 Ohm version as I thought it was better.
Thanks bookaboo, unfortunately I only have the 250 ohm model available for purchase :/ I do have a fiio e17 amp/dac and plan to get a fiio e9 as well so powering them wouldn't be a problem.
Unfortunately I haven't tried the HD600 or HD650 but from here-say I can understand the gist of what you're saying!
so donunus, when you listen to metal, do you typically use the 250ohm or the 80ohm version?