Unless you're talking large format 4x5/8x10, professionals are not shooting film anymore. The resolution coming off a medium format back is going to rival MF film pretty easily, and the convince factor + the cost savings if you shoot a lot (which studios do) make it an easy choice. If you're talking non-professional use then all bets are off. The local chapter of the ASMP just did a contest that involved shooting images of a roll of 120 film, unsuprisingly most of the shots were depicting the death of film-- frosted over rolls in the backs of freezers, that sort of thing. It's just not in use anymore.
For portrait shooters the choice between digital MF and high-res 35mm dSLRs has never been very easy. That said, the body that made that choice tough was the 1Ds2 that came out years ago. The 35mm cam has speed and ease of use on its side, which is a huge advantage when working on location or shooting people, and the resolution is plenty for most uses, but the MF backs have greater resolution (the latest ones are kind of astounding) and some other less obvious advantages like smoother tonal transition and finer detail.
Of course the astronomical cost of a medium format back has to be considered, but a busy professional is going to amortize that cost fairly quickly, though money is still money.
The current crop of super-high image quality dSLRs (5Dm2, 1DsM3, D3x, A900 ) seem to ever more substantially question the practicality of medium format for day-to-day commerical use.
At the end of the day it's going to be a question of what is needed to get a particular job done, which is why you rent things, and why many folks have both systems. Someone who shoots people for many purposes will certainly prefer a dSLR system on the grounds that it's faster and much more flexible, going to the MF when the resolution is a must, whereas someone who shoots immobile objects for a living will probably prefer a MF (or even LF ) system without a doubt.