Sigma 1612 or if you can find one used, the 1609 model. Has backlighting, and 15 or so other functions.

They are available in either wired or wireless. I have the 1609, and love it.

All my bikes, and likely Machka's, will be getting the 1612 progressively over the next little while, all wired. For randonneuring, redundancy is important, so I have my smartphone to track and provide route instructions, and the Sigma as my back-up and ready reference for distance (and temperature, of course).

Price depends on how much effort you want to go to, but the best I have seen for the new-model 1612 is around $AUD60.