@jamie026
Sorry for late reply, I was quite busy with this new year thing. I was careless to answer. If you are into Hip-hop then RE400 could disappoint you. Bass in them is quite low in impact. I will say quality of Bass is good. It is accurate, but very low impact. You could feel that bass is totally absent. However the driver of RE-400 is capable of producing good bass, If you can use equalizer to boost bass output then RE400 will be perfect (I am using Mach3Bass in Cowon Multiplayer).
SE215 will be better choice if used without equalizer. Highs are not that good as RE400 but again it matters mostly if you are listening Rock. You could also look at Ultimate ears 500.