Just to help out on the 60 side of the argument, you can fill a frame with a clover blossom, but yeah, you're close to lying on the ground.
And I have taken
a spider shot or two with it.
If you look at the MTF charts between the 60 and the 100 (non-IS), the 60 actually is the sharper lens of the two. But it cannot be used on a full-frame body, so if you plan on someday moving up to a 5D, you may want the 100 instead.