I made an entire subsystem for EAV data, in order to hold configuration information to be used by the entire enterprise.

There are stored procs, DTS packages, jobs, C# apps, web services and VB apps that access this data, which has been placed in lists. Those lists can be lists, or they can be lists that vary according to a second definable parameter, or tables that vary according to a definable parameter. Those 900 configuration tables we can can be abstracted down to 3 or 4 and the data normalized, since there are only keys, values (varchar(max)) and descriptions (also varchar(max)). We don't have a need to store binary information, and we use the TVFs to populate table variables that are then used in our queries (so casting is minimized). Even taking the hit where nested case statements would normally be used, it is actually faster than the nested case statements themselves and much cleaner and more maintainable. My goal is to have all our IFs and CASEs eventually use the configuration data so the entire enterprise is table driven. I guess the thing I'm most proud of is the index on varchar(max). Heh. Compute the SHA, persist it, close enough when you say 'the hash' = '@the hash' AND value = @value. Make sure there's indices on all the foreign keys and it's nothing but index seek. It conforms to my 'all your shit in one sock' algorithm, which places the configuration data where you know it'll be.