Thanks for the input, I think I'll go for the Omni, though I'll consider the E5 too,

The front headphone jack on my computer works while the back jacks hiss, and the front and back microphone input both have a hissing sound that only goes away when I use the sound card that my Logitech G430 came with.    I'm looking to upgrade to a Sennheiser HD 558 + Modmic 4.0 set-up in the...