[Ringoko]

I've had these headphones for around 3 years. I connect them directly to an iPod Touch, listening to spotify extreme quality and 320kbps MP3s. It sounds accurate I guess, but just a bit sparse and lifeless to my ears.
 
I'm not a basshead by any means, my preferred music is acoustic singer songwriter stuff. I just want something that sounds strong, clear, warm and natural.
 
Anyway I had a quick scan on Amazon and these are within my price range of £50-£100...
 
Sennheiser HD 380 Pro - £99
Sennheiser HD449 - £75
Sennheiser HD 518 - £82
AKG K271 MKII - £92
Sennheiser HD429s - £70
Grado SR60i - £80
AKG K240 MKII - £89
BRAINWAVZ HM5 - £70
Brainwavz HM9 - £85
 
I would prefer not to use an amp. + Full-size circumaural for long listening.

 

[cel4145]

M50s are not typically considered an accurate headphone, for they have some bass emphasis and somewhat recessed mids. Also, their soundstage is fairly narrow, so a bigger soundstage could give you a more pleasurable experience as well.

That being said, the M50s are a very good price/performance value in your budget range. So I think you'd be making more of a lateral move in class of headphone. Sure, you could probably find a pair of headphones that might suit your tastes better.