The distinction between "laboratory" and "development" board is insightful and something I never thought of. That explains why an EasyPIC4 or EasyPIC5 board doesn't really look that exciting to me (except for the ability to plug in a 128x64 GLCD to play with).
My approach to the TAP-28 board is almost completely opposite. A small, bare-bones board with essential features for programming and dedicated connectors based on function (ICSP, UART, I2C/SPI, PWM/servo and analog input). The idea is a cheap board that's more aimed at applications, and cheap enough that it can be used for embedded projects without much concern about cost.
**broken link removed**
TAP-28 boards are relatively cheap ($10 or 3 for $25) and are really an alternative to a hand-wired perf board, a bread board or making a custom board.
More information and some typical applications may be found on the TAP-28 page.