Mac OS X comes with an inbuilt, basic, no-nonsense PDF viewer that, well, just does the job. So, why not Windows? Heck, it comes with inbuilt Zipping functionality nowadays.
As the proud owner of a brand spanking new laptop with a fresh Windows install atop a self-formatted hard drive I'm reluctant to install any program I don't truly need that it isn't lightweight and hassle free.
After less than a day with the new PC I'm already finding I really need a PDF viewer. It's at this point I normally just install Adobe Reader. Well not this time. I've had it with Adobe's bloated software and it's annoying upgrade prompts. So much so that my old PC got downgraded from Adobe Reader 26 (or whatever version it's on now -- how can they warrant so many new versions!?) back to version 6. And even that prompted me all the time to upgrade.
No. This time I've opted for an alternative. After some digging around I went for Sumatra PDF, which is small, fast and does everything I want it to -- view, print, search etc.