Since you are asking the Enterprise IT forum, all our machines are imaged with the company image for the platform. This is true for desktop/laptop clients as well as servers.
(At home the last computer I acquired was hand-built, and of course clean-installed.)
This could probably depend on the company in question. I work for a small company and we don't image computers, though I have on occasion had a quick deployment VHD/VMDK pre-loaded with Server 2008 in x86 and x64 form for quicker server VM deployments. The same could really be done for desktop VMs too and I guess could be considered imaging.
In a general sense I prefer a clean install. If bought from a reputable vendor and from their business side of the house, there shouldn't be much if any bloat on the install but you never know. Even still there may be default configuration setups you don't want. I ordered a Dell PE 2600 many years ago and it came with 2003 Std on it but the array was partitioned with only like ~20GB or less to drive C. I lived with that for a while but eventually had to repartition it and reformatted it at the same time.
All of my personal computers are home built for the most part and are obviously fresh install. Name brand computers (laptops mostly) I'll use the stock install for a little while but its not long before something about it pisses me off and makes me format it lol.
For both home and work I usually break things in on the factory install just to see what's happening. Then shortly after that I do a formatted clean install. I usually like to check out which drivers the system has installed. This way I can grab the right ones from the net prior to the the reinstall.