I'm not sure about the current crop, but the first SLRs with video were limited to around 5 - 7 minutes recording due to sensor over heating.
That may seem limited, but I think most video users would find that they do not often take a shot for that length of time.
For me, it is a useful bonus feature, and one that I'll consider when I come to change my 400D. However, being completely honest, I'm still learning how to properly compose a still image. I take too many photos to find the few that I'm happy with.
If I took film, I would have to work out completely new composition techniques, and take even more gbs of film to then subsequently edit. And then, I'd probably feel I'd have to invest in some decent video editing software and then learn it. And by the time I'd done all that, I'd be ready for retirement or would be looking at a new camera and new software anyway.
In short, the still image is my priority. The facility to shoot off a couple of minutes of HD video should the situation arise is a useful and welcome feature, but not a dealbreaker.