Seriously though, the 32X in-game graphics are usually better than the CD ones, because the 32X can move a limited number of polygons (not sure of the actual polygon count on 32X, but it looks slightly better than the FX games on SNES). But the CDs have FMVs (FMV, or Full Motion Video, was just a fancy term they used for the digitized, highly compressed in-game videos and cut scenes that were used before DVDs came along) and high quality sound as well, because disks can hold much more data than carts. The animated sequences in games such as Lunar are pretty good, but the compressed "real" videos in other games are just awful. There are also a few CD games that are supposedly improved by running them in conjunction with the 32X, but the difference isn't all that great. I've also noticed that, when comparing several 32X ROMs to their Genesis counterparts, the 32Xs aren't much bigger than the Genesis ones, so many 32X games are just quick ports of Genesis carts.
As to which is better, CD or 32X, it's all a matter of taste. 32X gets the win for raw graphics power, but Sega CD wins for sound and sheer amount of content.