ps. sorry i don't know what you mean with "Which t did you do this shot with"...
Well, what t (time) did you use? The images on Flickr don't have the exif data.
I'm usually shooting macro subjects w/ 1/250 second (fastest flash sync), very seldom 1/60 second if I really need the background lighter. My experience is: with 1/250 there is no shake, and I can use the lens' sharpest f (both L and non-L: 6.3 and 7.1) aperture. This is the reason I said I doubt IS would help. On the other hand, with a large aperture like f20+ or focus stacking, you need a tripod anyway, so again no use for IS.
But of course, since the IS version is as light as the non-IS version, the L is the one to get if one can afford it. But I would be hesitant to buy a used IS lens, e.g. I heard about the 17-55 "weak is" that the motor does wear down more over time then the aperture.
uhm it's weird i can visualize the exif on that picture...
anyway on that specific one is 1/800, is not a really good sample of the IS, was an outdoor shot in a really sunny day...
the IS on this lens is really good, you can easily go down to 1/50 and lower (in reviews you can read of photographers shooting macro at 1/8 with that lens... my hands are not that still unluckly), that let you use smaller ISO values on handled shooting (on my camera i rarely shoot @ iso >= 800) and I have to say that i'm really happy with my handled shots and I'm not looking into spending other $500 on a macro flash.
But then again, if you plan (like in this case) to shoot some specific macros for a specific job you'll have all your gear with you (tripod flashes etc.) and the IS will be useless, but if you like me enjoy walking around with that lens in your bag and just want to take it out for a quick macro shoot on a subject that you just noticed without spending time setting up tripod, flash etc... well the IS is really helpful.
My advice to the OP is:
if you are looking to buy a macro in future rent the 100L and play with it handled too otherwise get the 180 if the price difference with the 100 Non-L isn't too big / you can afford it; I haven't tried the 60 but it just sounds too short, but this depends of course on your subjects