On ears with mid centric sound sig? Look no further than the V-moda m-80 or the Beyer dt1350. Problem with the akg k550 is that they don't seal well. I experienced this for myself when I kept having to hold them in place so that the rear part would seal. They're also quite big for portable use
Yeah, not really looking for on-ears. I'm thinking I'll stick with IEMs and either keep or trade the HD25s I have.