D3 or not D3 ... such a question ...
Well, unless your selling images ... the financial aspect of this one may be a little more than some people can stomach.
Also ... I not am suggesting any kind of conversion, but more a quick way to solve a problem without selling off property!
Most people, early in school, have limited financial involvement in their equipment. They had either been borrowing it from the the school or may have a couple of lenses at home, married to a $500 APS-C body. Chances are, those lenses are not the hottest ones around, either. ;)
SO, here comes the time to .. well, up the ante. Market forces are in play ... and you have to consider the well-positioned SONY system (<- click here for the inside skinny), when you make this decision, just to keep from breaking the bank. Like I might have suggested, if the financial aspect is of no consideration ... then this entire discussion is of little use. SERIOUSLY