I've been plundering AO3, so most of it is from there. Here goes.
Argus/Severus, Harry Potter.
Here. The Caretaker. Teen, 3k.
Thoughtful, with an extremely satisfying end. The tone is gorgeous.
Here. Servus. Explicit, 1k.
I've almost certainly already recced this, but it is a classic. Snape is... "unbefitting of a Roman citizen," definitely.
Tony/Steve, Avengers.
Here. Thor Should Never Be Allowed Internet Access. Explicit, 3k.
Priceless.
Phil/Clint, Avengers.
Here. Only His Ring Finger Knows. G, 1k.
Admittedly, I am a sucker for secrets and shocked responses, but this was better than I thought it would be.
Ronon/Rodney, Stargate: Atlantis.
Here. Satisfaction. NR (explicit), 17k.
A fantastic look at cultural differences and differing perspectives, and a tasteful treatment of a subject that doesn't often get such.
John/Ronon, Stargate: Atlantis.
Here. Fourteen Years. NR (mature), 12k.
A very introspective and well-written look at Ronon's life. At times beautiful, and at times terribly depressing.