ulrikft
Established
It's at the point where it's easily good enough. In fact it's way past that line. Photos that have collectively dropped the jaws of people around the world have been made on inferior cameras and formats.
Four thirds advantages lie in the superb, consistent and small lenses, the overall size and weight, and the overall experience.
By the way, if you look at DPreview's latest Canon t1r review you'll see the olympus e-620 has more highlight detail than the larger sensored canon, even in RAW, as well as more shadow room, and has the largest dynamic range in it's class. Pretty cool really.
If you research some Panasonic GH1 reviews, they are saying it has the same or better high ISO performance than the canon t1r and possibly others.
My first point in bold is what you need to hear though.
I have to disagree with your point in bold. What i can do with my d700 at 1/50 f/1.2 and iso 6400, when doing concert photography, people with an E3 can't do after me. That is just how it is right now. Is that a valid point for everyone? Of course not, but for me it _is_. And the dynamic range of the D3X, the ad900 and similar cameras is, as far as I have read tests and tried out myself, better than most alternatives if you shoot raw and process similarly over the entire line.
(disclaimer: I have to admit that I have no clue about what the Canon t1r is, is that an american brand name..?)