My favourite text adventures were a couple I played on the Acorn Electron,
Village of Lost Souls and The Hunt - both from Robico, great games full of atmosphere and depth and tricky little puzzles. They kept me going for years! I also liked Sphinx Adventure on the Electron (it came with it) even though its not very well rated, it was the first adventure game I ever saw and I played it for ages.
As for the Amiga Monkey Island I and II were/are brilliant - I just love the quirky humour.