Crimson, did you make your own sigs? If so would you mind learnin' me how to make them change from one pic to another like your middle pic(s)? I guess I could look it up online too but I figure we could get some good postin' out of this. 
Why Steve, since you ask, yes I did make my sigs (apart from the one from Killer).
If you're interested in making your own where 2 or more transition between each other, check out a tutorial I wrote on creating basic animated gifs a few years back. You can find it on my ageing (but it appears still useful) website:
Basic Animated GifsYou will need Photoshop for this one though...
Let me know if you have any questions/problems!