So here I am about to live out my fantasy of owning the 5D Mark II, but before I leap into the abyss I want to ensure I am makIng a sound decision. I currently own an XSI and 50 1.8 and in terms of IQ this combo continues to wow me. My main subject matter is portraiture with my twin 5 month old girls being my subject of choice. It's a lot of money to spend, but it may be a worthy investment after all I want the best pictures possible of my girls. I have owned pro bodies before (Nikon).