The DT770s are basshead cans... and not the best at it either, although very good for $120 or less...
I expect the 1540s to kick the crap out of those and compete with better closed headphones such as the Mad Dogs, Alpha Dogs, M500s, Sony MDR7520, Yamaha's MT220s, etc. etc.
Closed headphones you could look into:
Fostex T50RPs (MrSpeakers Mad Dogs!)
Ultrasone Signature DJ
Denon D5000
Yamaha HPH-MT220
Sennheiser Momentum (on-ear)
MrSpeakers Alpha Dogs
Shure SRH840
Denon D600
Sony MDR-1R
V-MODA M100
Ultrasone Signature Pro
M-Audio Q40
KEF M500
PSB M4U 1
Monster N-Pulse
and a bunch of others.
Most comfy? Mad Dogs, Alpha Dogs, Sony MDR-1R (I guess they are coming out with a newer one as well...), Denon D600, PSB M4U 1, KEF M500s... Haven't received the 1540s so not sure how they will fare sound-wise.
If you are looking for recommendations, please check here:
http://www.head-fi.org/f/7840/introductions-help-and-recommendations
Thanks