Most people seem to use 2 or 3 Launcher or Home Screen Replacement apps on their Android device.
I know people who switch from one launcher to the next trying to find the best home screen possible.
It seems that there is no ideal home screen that really has all the features people are looking for.
I've used ADW Launcher and Go Launcher and started working on Claystone, a new home screen replacement for my day job. It's tough to get it right and give people the features they need the most.
I am a big fan of HTC Sense. Elegant design, great widgets, and not overly complicated.
For me the features I miss the most are:
Not being able to view content like a web page or videos, photos on my home screen (and having to launch Android Apps to do it). It really disrupts my home screen experience.