I went from an iMac to a Mini and am very disappointed. The mini needs everything. Speakers, display, optical drive, etc. it really is a step back with all the clutter.
The only difference is a good screen. Yes that adds a cable.
If you want ethernet, you want, the imac has 2 cables
If you want a decent keyboard with numpad, you want, the iMac has 3 cables
If you want a backup drive, you want, the iMac has 4 cables.
If you want an optical drive, you are stupid, you don't want, don't bother
If you want speakers, either way the built in of the Mini is fine (for working background music), actually I'm surprised how good it sounds, but if you want more (then you want more on your iMac), your iMac has 5 cables.
The difference remains 1 display cable. But 5 or 6 is not that much different.
If you buy the right display, you can remove many clutter from your desk with a mini: 1 cable to the screen, the mini somewhere under your table, and 2 cables from the screen to wacom/mouse and keyboard.
You have 2 cables less than on an iMac.
Another pro with the mini: you can use all black cables and you don't get input devices that suck and can be trown in a drawer. With an iMac every thing has stinking white cables (left overs from the old G5 and early Intel mini's). With a Mini you can buy a black keyboard, a 1$ black power cord (replacing it on the iMac looks weird) and very nice black display cables that fit right in without white ugly adapters.