Web: When you are trying to troubleshoot internet connection issues, knowledge is power. Viewdns.info consolidates 21 different tests on one handy page.
There's a lot of good stuff here, from "Is this Site Down" to "Traceroute" and "IP Location Finder". You can find all this information in other places, of course, but this site puts it all onto one page. The one thing missing is your current IP address, but we've got an easy way to do that too. Check it out at the link below.