Hi Ben ..
It would be fun to see what you can get out of a LPC1768 (mbed), just some kind of project, as long as it contains Display, Led, and some type of relay.
Now it is only up to you what the project will be used for!
I use LPC1768 in my own projects, as this dev board not collars for the great knowledge of C + + it is a fine beginer DEVboard ..
Good luck