Hi
Just wanted to say thanks for everyones input and to tell you the outcome..
I purchased the Beyer DT990 Pro's as suggested by Hi-Finthen. I set it all up how I wanted and plugged those cans into the Heed CanAmp.. The cans definitely deliver on Bass with the Heed CanAmp

It's a little puzzling because the 595's that I have, give out great bass on my PC, but not so much on the Heed - But then, the 595's on the PC are used for music and the DT990's with the CanAmp are for TV/DVD viewing...not sure if that has anything to do with it..
All in all, it's worked out a treat
Thanks again everyone
Jon
Edit: Oops, sorry I didn't see there was a second page! Yes you're right TomH, I think I got used to the heavy bass with the 595's on my integrated amp.. But the hissing was terrible.