Jotspot demonstrates this nicely, but it seems to hide the actual table data - perhaps storing it in a external datastore associated with the topic. But it is nice to store the table information in topic itself. (Bulk editing, no problems in renaming ...)
But unfortunately there is no standardized syntax for table within a wiki topic (of course we don't have any standard as of now). Wikipedia is evolving to be a great centralized resource, so might propel a standard creation process.
In this context, a useful link is discussion on table syntax:
Help:Table - From Meta; discussion about Wikimedia projects. In particular, even using XHTML as table syntax would help a lot: It might allow someone to create a nice table editing tool - with plugin approach to add semantics such as Spreadsheet ...