i read your forum post too,
firstly i think the key problem here is the point of focus, the expression and face is fine but the focus and principle sharp area is the hair centred behind the eyes. a portrait in many peoples opinion should be sharp in the eyes to the exclusion of all else.
the lighting is pretty flat although credit to getting catchlights in the eyes, the flat light is not particularly bothering me, but i think it has a blue caste which is not helping the skin tones. this can be corrected in PS or any software package either by using the eye dropper or colour balance tools
with digital it is often necessary to make post camera adjustments and to be honest this took me a long time to accept having many years using transparancy film where i expected immediate results. you need to adjust colour balance, increase saturation a little and have an attempy at sharpening. the best way would be high pass erasing all but the sharpening to the eyes. tricky to pick up though.
it may be, im not a Canon user, but many things can be adjusted on the settings of your camera. ie extra sharpness, extra saturation etc and it may pay you to investigate this if you want results straight from the camera.
i notice you shoot Jpegs, please learn to use raw. its the first lesson in pulling in changes after taking and will give you a lot more options without losing quality of the file.
the eye contact and expression are rather nice and its altogether quite a nice portrait with a few minor niggles.
hope this helps,