Just had to drop a note that I think both Canon and Nikon have edges on each other, just in different areas. Nikon, for example has better flash exposure/technology. I also think the D200 is probably the best digital camera availble right now. Not that it matters much... You won't be unhappy with either brand.

At one time I really wanted a full-frame digital sensor, but now I'm not so sure. The cost of manufacturing the larger sensor has to be incredibly high; yields go through the floor with dies that big. Still, with larger pixels you get better signal/noise ratios. The larger sensor also gives a wider angle view but the smaller sensor gives better zoom.

Also, the smaller sensor allows for smaller lenses which means less cost, less weight, and less distortion. In the end, which is better depends on the task it's being used for.

Nikon makes excellent cameras, no doubt. I have had an art student asking me about cameras yesterday and after he revealed that his dad used Nikon for years, I told him to get a Nikon too. There is no doubt in my mind that both Canon and Nikon make excellent cameras.
I wasn't aware that the D200 had a much faster sync speed. This would make the camera a good choice for photo journalists. I have once been at a graduation event, and that was the only time I maxed out the sync speed on my 20D (with a long lens in the 200mm range). If you are shooting with shorter lenses, the sync speed will not an issue. The crop factor will also be useful at such events (graduations, press conferences ...).
But for nature photography the Canon 5D defenitely has the edge. With approximately the same resolution and twice the sensor size, the pixel sites will be twice as big, making the 5D one of the lowest noise cameras in that range (outperforming the 200D). For a Nature Photographer such as myself, this makes it a better choice (despite the obvious fact, that I have been using Canon for a long time and have all Canon Equipment and Lenses). In Nature photography, the flash sync speed is not as important as low noise (especially at higher ISO settings).
You are right, the cost for manufacturing a sensor twice as large, is at least 4 times higher. That only proofs my view, that Canon is better in technology, since they are capable of producing such a sensor. I am sure, that if Nikon could provide a product to compete with the 1Ds Mark II (introduced in 2004 by Canon) they would. So if Canon has the top line under control, they most likely know how to deal with medium range sensors (20D, 30D, 400D ...).
Most of us will decide by our history (if I spent thousands on Canon lenses, I am less likely to switch to Nikon). For those of us who are not constrained by equpment we own, we can choose. If you want fast action, the Nikon D200 or the Canon 1D Mark II (not the 1Ds) are both excellent choices). Canon has been able to push the top end a little more than Nikon and the L-series lenses are some of the best in the market (if you can afford them).

Regarding Canon's supposed edge in sensor technology, one cannot reasonably conclude from the data available that Nikon lacks the capability to produce a full-size CMOS/CCD chip. Sony, the world leader in image capture technology, also does not (to the best of my knowledge) produce a full-size sensor, though they could surely do so.

Rather than demonstrating a technology gap, I believe that it is far more likely that Nikon and Sony have chosen not to enter this market segment due either to low margins or insufficient volume. First and foremost, they are corporations seeking profits, and there probably isn't a viable business case for such high-end professional models. While Canon may be successful as the first and only seller of such items, the entry of another competitor into the segment might eliminate profits for both. As such, Canon is able to retain a monopoly in this area until a favourable change in the market occurs.

//Edward
Business Analyst
Newbie Photographer

"While Canon may be successful as the first and only seller of such items, the entry of another competitor into the segment might eliminate profits for both."

Since when does this prevent a new competitor from entering the market? If Sony will think they can do it cheaper and better, they will surely try and kick Canon of their throne.
How many luxury car makers do we have? None of them leaves the battlefield to their competitors just like that.

Due to impurities, it is extremely hard to make sensors larger (double the size will give 1/4 of the yield assuming the same impurity densities). Plus you will have more waste (round wafer + sqare die = cuttings). So the cost may be more then 5x higher (compared to the 1.6x crop sensor). Only if you have the process capabilities can you make a product like this and still turn a profit. There are even larger ones available (Hasselblad & others) but you will pay a fortune for those.
I agree with you, that both Nikon and Sony could easily make a full frame sensor, but I am not so sure they could mass produce it and turn a profit.

Of course this is not proof that Canon builds better sensors. In this regard I agree with you.
Canon has demonstrated that they can built those larger sensors and mass produce them at a margin, and thats remarkable, seing that noone else has ever tried it. If it weren't profitable, they wouldn't do it. That they are now capable to offer the 5D which has a full frame sensor but a much lower price then the 1DsM2 is just proof to me, that they have made significant progress in their manufacturing since the introduction of the 1DsM2.

As you said, those are corporations seeking profits and if Sony could make a profit by offering this, I am sure they would do it. Making extremely large LCD TV screens also costs a lot more then making smaller ones, and still lots of companies play in that field.

I have to say, I never looked at Sony's cameras. Until a couple of years ago they had nothing much to offer in terms of SLR and once I have all my lenses, it would take a serious shift in competencies (Canon drops the ball) for me to switch. Recently I have seen some cameras come out and the specs looked good, but I never really bothered to check them out.
Sony has the money and the size to become the world leader in this technology, but I haven't seen it happen yet.

Surely, we could argue forever on who makes the best sensors. My blog posts are usually biased and I should have written it down like this (I am a Canon owner and for the most part I am satisfied despite some recent arguments).

Thanks for your comment Edward. I really appreciate your opinion and I love to have a discussion.

which is better for moderate skilled photo taking pctures of family,lanscape,basic sports,all for fun:
canon g7 or s51s?

I personally own a Canon S3 IS and i like it very much. Both are excellent cameras. On the S5 i like the swivel screen for discrete shots.

Both cameras don't support RAW (the G9 does but costs more). I like the reach of the S5 (the lens) and I would prefer it over the moderately larger images. On the other hand my S3 is not exactly a good camera for sports, since its shutter delay is too long and continuous burst rate is not sufficient. I am not sure if the G7 will perform much better in this area. However I am being spoiled by my Canon 20D.

Otherwise both cameras offer sufficient levels of control and manual options for lots of fun. I like the formfactor of the G7 better but in the end I went for the S3 because its extremely cheap now on Amazon (Canon S3 on Amazon) and because of its swivel screen that lets me shoot pictures over head and from the waist. The incredible reach of the 12x zoom lens with Image Stabilization was well worth the price for me. The G7 won't offer you that much reach.