After reading the LikeWhoa thread I thought I would pass on a tool.
Reliable hosting companies are rarely down, yet you might find you cannot get to your server. Often the problem is at a NAP (Network Access Point) where various backbones route together. There is often latency at NAPS and sometimes router flapping as routers are reprogramming their tables.
The best tool I have found to find out what is happening is
to go to:
http://www.traceroute.org/
You can jump on a server or router anyplace in the world and trace to your server and see if the trace dies at the host or before the host.
Hope this helps in the future.