A great place for a stroll any time of the year is around Minnowburn in South Belfast, walking up to the Giants Ring, a Neolithic Henge monument.
Minnowburn is, as the name suggests, a burn that takes it's name from the minnow that would be found there. It's a regular enough walk for me when I'm not really in the mood for the hills or coast. I could ramble on about the history of the place but I'll just let my collection of photos over the past few years speak for it. Roughly in the order of the walk down to the river, up round to the henge then back down the hill.