The Treacle Tart - two fics: Still Life, because the idea of Severus with a camera, and the way it turns out, is just wonderful. And The Very Air He Breathed because the idea of Severus coming to understand things about Lupin just by really watching him...rowr.
McKay's The Way of the World will always be one of my absolute favourite comfort fics. Watching their relationship develop, all the lovely warm-fuzzy feelings...Mmm.
If He Tries Anything by Pocketwitch. Snape deciding to select a partner by logic is priceless, and Remus' reaction...lovely.
Double Happiness Masala. Remus & Severus, non-magical AU, and yet it's just so magic. There's such deep emotion and...guh, it's lovely.