Well, unless you have deep pockets these new lenses probably will not affect you, but feel free to go out and rent. The first two are improvements of super-telephoto lenses the EF 500mm f/4L IS II USM and the EF 600mm f/4L IS II USM. Both get improved elements for better images specifically reducing chromatic abrasion as well as newer and improved IS systems. Each lens is also lighter and more durable than the lens they replace, but at $9,500 and $12,000 respectively the audience is limited.
The EF-S 18-55mm f/3.5-5.6 IS II updates the kit lens for the Digital Rebel lines, but there are no enhancements in the optics or usability. DPreview.com reports only cost savings for Canon with no changes for the end-user.
Finally the EF 200-400mm f/4L IS USM Extender 1.4x telephoto zoom lens for those looking beyond the reach of the standard 70-200mm zooms offers a much faster and lighter substitution for the EF 100-400mm f/4.5-5.6L IS USM lens. The new lens features f/4 throughout the zoom range as well as a built in Extender giving 280-560mm effective focal length.