Not sure about the eyeone you got, but on my spyder there are two things to calibrate to. One is the brightness which I fiddled with the brightness/contrast (a lot) to get it around 100 (which is supposed to be comfortable reading level). Then you balance the RGB sliders until the other number (which I forget what it's called) is as low as possible. 0.0 is perfect, i think 0.2 is really good, 0.5+ is bad. Mine started at .4 and had a noticeable color cast. After calibration it was down to 0.23. The before and after was quite noticeable.
So either your monitor is pretty good right out of the box, or maybe you havent gotten the target numbers to where they should be.
I read up on some reviews before i bought my monitors, and some monitors calibrate real well. Others dont. Acer 2216, which I was considering for a while due to price, were really good out of the box, but calibrating didn't improve them any further. The Asus vw222u that i got was "ok" out of the box but calibrated better than the samsung 2253bw (not available anymore) and it was a lot cheaper which is why i got them. I wonder if your monitor falls into that category?