If you need the 12.8 megapixels, if you need the full frame CMOS sensor to get your wide angle shots right now....I would say it's business and this helps your business.
There are many tweeks and improvements on the 5D over the 20d and lets not get into listing each and every one of them right now. But if your work would benefit from the 2 aforementioned things, I would look at a 5d. Otherwise, JP's advice on glass doesn't sound all to bad.
Gotta keep this in mind, this isn't the last full frame sensor Canon will be putting out, this is the beginning of a trend for their digital SLR's. In 12-18 months you will see another version of a full frame SLR from Canon.
So, in short, its between want and need, right now I would focus on the need.
....it's still a great camera and I want to get my hands on one again [img]/ubbthreads/images/graemlins/smile.gif[/img] But my work doesn't need that right now.....and, i'm sorta broke [img]/ubbthreads/images/graemlins/smile.gif[/img] Want and need have no effect when you have other things that classify as, "priority" [img]/ubbthreads/images/graemlins/smile.gif[/img]
Best of luck in your Canon quest, 20d is still a damn fine camera. 5d a better camera, but I dunno about $2,000 better....then again those canon rebates are kicking in again [img]/ubbthreads/images/graemlins/smile.gif[/img]