As said, servers are owned by are located at our hosting provider's facilities, where they have three or four backbone Net connections connecting their server facility (which contains thousands of servers). And yes, server rooms are extremely well air conditioned, power supplies are typically backed up by diesel generators, etc (some details: http://www.theplanet.com/facilities/index.html).
Most of the servers (actually 7) are Dell PowerEdge 1800 servers http://www1.la.dell.com/content/products/productdetails.aspx/pedge_1800?c=an&l=en&s=bsd ie. 5U rack servers, so they take 35U of rack space. Our download server is hosted at another location, and is a 2.4GHz Celeron with 80G+200G IDE HDDs. The others have a 73GB Ultra320 drives in various configurations. The image server Petteri mentioned earlier handles also log processing and analysing, log archiving, backups, DNS, load balancing and a number of other, smaller tasks.
damn those server storage environment are overkill. over 500 smoke detectors and those megawatts generators.
Obviously we don't have to deal with Dell directly. The Planet staff handles all the support issues regarding our hardware.
i noticed that the planet used powerware for there battery back-up system. i used to work there. glad to know i could help.