Depends, depends, depends. I dug out my Canon 1Ds and 70-200 f/2.8 IS for a special event last weekend... and I'd forgotten just how big, heavy, and clunky the thing actually is. Especially packing the 28-70 and 16-35 to go with...
I could, in fact, see the Micro 4/3 and APS-C sensors in a prosumer P&S "stealing" the market from the DSLRs, especially as their low-light quality improves. Studios are using 6x4.5 30MP and up medium format anyway.
So, camera phones, APS-C, DSLR, and MF. Seems like that covers all the bases.
I have an Olympus Micro 4/3 camera and it takes outstanding photos. My wife has a very good Sony 10 X zoom point-and-shoot and we've compared side-by-side photos a handful of times. There's an instantly noticeable difference in quality. Keep in mind it would be very hard to find a phone that takes as good pictures as her Sony.
Also, the lower the light the more pronounced the advantages of a large sensor camera become. Pixel count will always be a relative non-factor opposite sensor size.