I use sennheiser 590's as my primary computer headphones mainly because they are the most comfortable headphones I’ve ever worn, and as I'm wearing them for extended periods of time it was a key issue for me when buying.
Personally I’d strongly recommend, Audio Technica ATH-AD700's or ATH-900's (both very comfortable) providing the source isn’t too terrible, as well as those grados / Alessandros for the price.
I find that a lot of the lower end sennheiser cans are really overrated, and more often than not you can find better quality headphones for the same price as senns if you do a little research and auditioning. It all comes down to preference really, headphones vary in sound stage and signature, some people may really like what others cant stand.