1st set: exposure +4 (max) in Lightroom.
2nd set: exposure 0 + Lightroom noise reduction at 100 (max).
3rd set: exposure at -1.5 with noise reduction at 100 again.
The first set is totally exaggerated and not very useful.
In the second, it looks like ISO 3200 on the 50D is fine and 6400 might be useful.
The 3rd is a good example of how I try to use high ISOs; overexpose by a stop or two and darken in Lightroom. In this 3rd example I'd say 6400 is fine and 12800 might be useful.
sRAW modes seem to improve the sharpness and decrease the noise (more testing to do). I was expecting to see more of a difference between sRAW1 and sRAW2.
