Audio Technica CK10 iems
Forget the Klipsch X10s (no idea why these are so highly feted by What Hi-Fi, given their lousy build quality and alright-but-not-fantastic sound for a single balanced armature iem) - my own personal recommendation is the CK10. Ok, they're just over £200, but for that you get tanklike build, the best cable in the world, brilliant comfort levels and, more importantly, superb sound quality. You can't go wrong in my opinion.
Anyway, just thought I'd put a shout out for these incredible earphones. Twelve thumbs up.