Thinkig of PWS? Naughty, naughty, bad, naughty!!!๐ Apache always be the main contender for whatever OS you're planning to use....
Odds are you're going to be moving to an Apache box for production anyways, so using Apache will come closer to mimicing the deployment environment. If you're going to be deploying to IIS, PWS doesn't really come close to mimicing IIS... so you're better off on Apache again. It's for some pretty damn good reasons that Apache holds more marketshare than every other httpd server combined.
Regarding PWS's suitablity for anything, even Microsoft recommends against using it and does not support it/release security patches for it. Of course, they really just want you to buy into the NT OS and use IIS instead..... so take that with a grain or five of salt๐
There is another smaller server which I've never used, but might fit your bill. 'Tis called BadBlue and it's found at http://www.badblue.com/.
geoff