Just switch my operating system to Vista, and my biggest complaint about it is that it breaks my Apache HTTP server. The server still runs, but very slowly. The symptom is as follow: every time I reload a web page from the browser, there usually is a 2-3 seconds delay before the loading sequence starts. This shouldn't be happening because I serve all my files locally, so I expect no delay at all. Also, this behavior does not occur in XP.
After some excessive searches, I found a forum post (forgot the URL, will update this when I hit the site again) that suggests uninstalling Zone Alarm will resolve the problem. I gave it a try since I was in nowhere in solving the problem. Surprisingly the uninstallation did cure the delay issue of Apache. Beware that you HAVE TO restart Vista after uninstallation, otherwise you will not see the changes.
That's right, I uninstalled my firewall. So replacement? I like Zone Alarm and enjoy using it, but it doesn't seem to be very stable on Vista. However, I've found another great firewall product, Comodo Firewall Pro, which is a commercial grade firewall free of charge.