Note, this is a partial response to Sam Gentile post about ALT.NET.
Enterprisey - This is a derogatory term, used to refer to a system whose design or implementation is overly complex compared to its supposed function. Often the term refers to the usage of anti patterns such as Everything is configurable, Executable XML, etc. Those systems are consider bad because a simpler design or implementation would have achieve the same purpose, at far lower cost, with greater maintainability overall.
Enterprise Software - A common term used to refer to systems that usually run a core part of a business. Often those are mission critical systems, which interact with many other systems in the organization in many interesting ways. Enterprise software is considered hard because it often need to mix technological capabilities with the business logic, and be flexible to handle changing conditions as the business evolves.
Enterprise Software done right - A system that handle those complex issues while keeping complexity to the minimum necessary to handle the actual requirements.
Enterprise Software done wrong - see Enterprisey