For me, it's about the anticipation of getting your end results after maybe a few weeks of shooting.... yes a roll of 24 exposures will last me the same amount of time as a 4GB memory card on my dSLR!
It's about boundaries; some people need them, some people don't. I don't shoot fully manual with my film body, prefering Av, but I view full program mode to be cheating. The thing is, that it forces you to think of what you're doing. Your ISO is fixed, you set your aperture and you can see if your shutter speed is too low, or too high for the camera (I can only go up to 1/1000!).
Yes, you can mimic this on a dSLR... fix your ISO... select Av... but it feels like the camera was never designed for this. The camera wants you to give it the control and its all too easy to give in to that. If you do, you lose what you were trying to achieve in the first place. The picture then comes up on the back of the camera showing you what it did... like the camera took the picture, not me!
I liken it to going into a burger bar and ordering a salad. You may have the self control to do that, but I sadly do not!
Besides, there's something aboutthe look of film that you just can't replicate in software.