Julia has no headamp and also has no headphone jack. Investigate ESI maya--it has a dedicated amplified headphone out. I can only compare x-fi to e-mu 0404 usb, and x-fi sounded a bit more metallic in the highs, a bit more smeared in the bass, and overall the timbre is less pleasant and there is a tad less detail. However, in absolute terms the differences are fairly subtle. Juli@ is slightly less detailed than 0404usb, if the digit-life review is to be believed (and I don't see why not, their testing equipment far exceeds what 99% of head-fiers have). At the same time, the difference may not be as noticeable on HD 595. Also, it seems Juli@ has more stable drivers.
Overall, I think you'll be fine with any of these cards. Just keep in mind that Juli@, 1212M, 0404 (internal) will not properly drive your headphones without an amp, not sure about audiophile 2496.