I realized I haven't done enough House fanfic recommendations. So I'll start off with it.
House
Downpour by morgan72uk Part 1,
Part 2,
Part 3,
Part 4,
and Part 5. - Summary: In a storm things get washed away
Your Hand In Mine by Hihoplastic - So depressing but so good. House/Cuddy and the end of the world.
Alchemy by Melissaisdown - I just love her writing style.
Angel
Heat Stroke by Starlet2367 - SUMMARY: "Please tell me there's a Kwik-E-Mart next door," Angel said. Cordy slapped him on the arm. "No, dummy. There's nothing but desert. Flat, empty, stupid desert."
Queen of the Night by Startlet2367 - SUMMARY: In order to have a future, Cordy must face Angel's past. Spoilers up through Dad. An ACAngst Plotfic of the Moment. Nominated for 2002 Halo Awards, Best Angel and Best Romance.
Harry Potter
Voiceless by Musca - Description: “Because I felt it. While you were missing and ever since then, I’ve had this feeling inside my skin, like I can hear the blood flowing inside me. Professor Tiresias figured it out.”
Vox Corporis by MissAnnThropic - This is one of the first H/Hr fanfics I read. It's a classic.
Taste by KateJ. - Smutty goodness.