When you're shooting for a truly exaggerated point of view, twist on the Pro DV Series Fisheye Adapter. The Fisheye gets you the widest view possible, with extreme barrel distortion.
The fisheye exaggerates depth, pulling nearby objects closer, and causing distant objects to recede into the background. A fixed adapter, the Fisheye doesn't allow for zooming - but you'll want to stay at the wide end of the range anyway, for the most pronounced effect.
Century makes two versions of the Pro DV Series Fisheye - one for the 16X lens and another for the 3X. Starting with the already wide angle 3:1 makes for even more impressive coverage. So while the 16X version offers an approximate effective focal length of 2.7mm (an 85° angle of view), the Fisheye for Canon's 3X lens achieves an approximate effective focal length of just 1.5mm (a 116° angle of view).