As you know Netcraft regularly publishes its web hosting companies top list. The providers are ranked by reliability of their network. According to metrics web agency, Rackspace tops the reliablility list for September 2006. Managed providers Datapipe and Oregon based collocation and dedicated host Katarre are ranked second and third.
Kattare, a web host registered since 1998 is a company that i see among the most reliable ones for the first time. The other interesting thing is that all ranked web hosts (or at least 8 of 10) are Linux based.
Rackspace gets the first position for the fifth time in 2006. Netcraft also reports that the managed web host has found a their regular place in web hosting reliability rankings since 2003.
The Netcraft measurement technology monitors 50 leading hosting companies worldwide. The web analyst company measures the uptime at 15 minute intervals from different points around the globe.
There are three Italian companies among Top 50, one German, one Canadian, a few UK hosts, as well as the Chinese hosting company China Net Center.
GoDaddy, 1and1, Aplus and Web.com are some of the shared hosting providers that find place among the first 30 hosts
The whole web host reliability list can be found at http://uptime.netcraft.com/perf/reports/Hosters.