I used both XAMPP and WAMP in Windows and found their general performance and reliability to be pretty poor. I guess when you install them they aren't exactly as optimised as they could be.
So, I use Zend Server Free Edition now.
It includes lots of bloat, actually, but I tend to just install the Server part and the bits relating to performance and caching (Zend Optimizer etc.) and it works great.
It always wants to install your htdocs folder in C:\Program Files\Zend\Apache2\htdocs though so in later version of Windows you'll get User Account Control problems so you will either need to move htdocs to another location that is writable (my documents, etc.) or make your htdocs folder specifically writable and override any inheriting permissions.
I had the same thing, I think but it wasn't Skype related.
I think something still had a binding on port 80, presumably from the previous web server. One thought is, before uninstalling your existing stack, change its port to something obscure like 8888. That way, you know before you install the next one port 80 shouldn't be in use. Just in case something in the uninstall of the old stack doesn't release it.
I'm currently using EasyPHP and it works fine. I did have a permissions problem with Win7 that I tracked down to having it installed in the Program Files folder. Moving the install to the drive root fixed all that. And if you use Skype you'll have to change ports...
I've used XAMPP for years and never had a problem with it until recently, when I upgraded to one of their newer versions I couldn't work on vB anymore, since it doesn't support PHP 5.4 yet. I downgraded it and works fine for me.
I like being as close as possible to my "live" environment, so I run a Debian 6 virtual machine with dotdeb repositories of nginx, php, and mysql. Once I am finished I can just suspend the VM and it all goes away until I need it again. Making snapshots before I do a change/update is also a great thing.