This may be an extensive list but that is because a server can be very vesatile and you need to explore what you really need in a server before you just buy one.
Applications Servers
Application servers occupy a large chunk of computing territory between database servers and the end user, and they often connect the two.
Audio/Video Server
Audio/Video servers bring multimedia capabilities to Web sites by enabling them to broadcast streaming multimedia content.
Chat Servers
Chat servers enable a large number of users to exchange information in an environment similar to Internet newsgroups that offer real-time discussion capabilities.
Fax Servers
A fax server is an ideal solution for organizations looking to reduce incoming and outgoing telephone resources but that need to fax actual documents.
FTP Servers
One of the oldest of the Internet services, File Transfer Protocol makes it possible to move one or more files securely between computers while providing file security and organization as well as transfer control.
Groupware Servers
A groupware server is software designed to enable users to collaborate, regardless of location, via the Internet or a corporate intranet and to work together in a virtual atmosphere.
IRC Servers
An option for those seeking real-time discussion capabilities, Internet Relay Chat consists of various separate networks (or "nets") of servers that allow users to connect to each other via an IRC network.
List Servers
List servers offer a way to better manage mailing lists, whether they be interactive discussions open to the public or one-way lists that deliver announcements, newsletters, or advertising.
Mail Servers
Almost as ubiquitous and crucial as Web servers, mail servers move and store mail over corporate networks (via LANs and WANs) and across the Internet.
News Servers
News servers act as a distribution and delivery source for the thousands of public news groups currently accessible over the USENET news network.
Proxy Servers
Proxy servers sit between a client program (typically a Web browser) and an external server (typically another server on the Web) to filter requests, improve performance, and share connections.
Telnet Servers
A Telnet server enables users to log on to a host computer and perform tasks as if they're working on the remote computer itself.
Web Servers
At its core, a Web server serves static content to a Web browser by loading a file from a disk and serving it across the network to a user's Web browser. This entire exchange is mediated by the browser and server talking to each other using HTTP.
