I believe the Canon EOS-1D X represents an exciting twist in Canon's line up of cameras. With the amount of photographers in the world today, and the hobby of digital photography still growing rapidly, the digital SLR market is huge, with identifiable market fragments and niches. The release of a 1 Series camera is both 'big news' for professionals looking for a new 1 Series, as well as for those not (or 'not yet') interested in 1 Series camera bodies. Like Formula 1 racing car technology, which affects every day cars on the road (after some time), a lot about what the 1D X is will eventually impact other cameras. I'll put it out there and say, the 'news', changes and technology of the 1D X is more exciting for me than the actual camera body itself that was announced 18 Oct 2011.
Currently I do not own a 1 series camera body, nor a full frame (FF) - though I have used full frame in the past. The Canon 7D is my current camera. When the 7D camera was announced about 2 years ago and its specifications were detailed, I knew that it was the most suitable camera for my needs (mainly accurate, fast AF, generally customisable body, drive speed, flexible ISO).
As an 18 MP FF camera, the 1D X is obviously quite different to the 7D which is an 18 MP 1.6x crop (APS-C) camera. I expect the 1D X will be an awesome low light and 'action' camera - with very low noise at relative ISO settings, very strong AF capabilities and the 12fps/14fps drive speed seems awesome. I expect some of the sensor R&D as well as camera body development will trickle down to benefit future cameras like the 7D mk II. I don't particularly want more than 18MP (for my personal needs). I've found the 7D's 18MP very handy for cropping. Dynamic range and ISO noise are important trade offs when more pixels are in a sensor.
Needless to say camera bodies can be used flexibly (eg I used my 7D very successfully for landscapes). However, just like many other commodities, there is a 'better tool for a certain job'. I think that the 1D X will indeed be a very suitable camera for professionals (or 'very enthusiastic hobbyists') at this stage... particularly with the 2012 Summer Olympics coming up in 10 months time. If the AF is very good - the 1D X is bound to be a winner (ie good seller and great tool for such sports), particularly when matched with some of the recently released tele lenses.
Over the years I've bought 8 lenses. 3 are EF-S type (ie suitable only for APS-C cameras), while the other 5 are Canon EF (ie suitable for both APS-C and FF camera bodies). I love taking photos that bring others joy, whether that's sharing something of the beauty in nature, or capturing a precious memory or 'event'. I take a wide range of photos - from landscape to macro to children camps to wildlife to family & church events. The areas of photography that I rarely indulge in are portrait, sports & architecture (though I do a bit of each of these occasionally, and very casually). My Canon 7D is a flexible tool for my needs, and I'm very happy with it.
I have little doubt that the new Canon EOS-1D X will do any type of photography better than my 7D, except perhaps for some wildlife situations (eg small birds) where the higher pixel density of the 7D might present one advantage. However I doubt that I'll ever buy a Canon EOS-1D X or other 1 Series Canon camera - mainly because of 2 factors: A) price (even though I can actually 'afford' it - I prefer to spend, invest or donate such money to other causes and B) weight (although I am reasonably fit and can carry a 1D, I prefer the comfort of a lighter combination).
Having written that, yesterday's announcement of the Canon 1D X still leaves me very excited. I can see Canon have thought long and hard about photographic needs, and answered with a powerful and I trust very effective tool. I expect there will other camera bodies announced in time which will cater to the studio, portrait, landscape segments (these probably having more than 18 megapixels) as well as the non-pro segment (cheaper / lighter).
The R&D and research that Canon have presented in the 1D X give me an indication that we can expect more good things to come. That's where I've got my eye on. Not that I expect my 7D will need replacing any time soon (unless I inadvertently damage it somehow). If there is a product to be announced that might convince me to buy it, that would be a Canon 50mm f/1.8 with ring USM, great bokeh, good contrast and sharp corner to corner wide open, and a close 'minimal focus distance'. Now that's what I'm really waiting for!
Thanks Canon for the new camera and innovations. Thanks to this website for the information and the positive posters for thoughts and being an online community.