Trying to figure out what formats I want to shoot in

We've just ordered an XF100 at work, and this will be the first professional level cam I've handled. I'm trying to figure out the best format to shoot in based on my needs. I will be trying to shoot a lot of "stock" footage that I will be able to use at work when I need it. I won't be outputting anything higher than 720p. I do want to be able to play back some of these clips in slo-mo depending on my project.

Should I:
- shoot at the highest 50mbps setting at 1080/60i and downconvert to 720/60p
- shoot at 35mbps 720/60p and not worry about having the higher resolution space for panning if I need it
- or even shoot at the 25mbps 1440x1080/60i for improved disk space?

Aside from the obvious resolution differences, and ignoring the 4:2:2 color space, would I notice a big quality difference between the 50, 35, or 25 mbps shooting modes? Would I really need the 4:2:2 color space if I'm not chroma keying or color correcting?

Thanks.