Two of my favorites:
Adagietto, a Sam/Daniel angst fic that had me bawling into a wad of tissues. The writing was just so beautiful, it made a theme that could have been horrible under another author's purview and made it so good.
The Pieces of My Life, a CSI/West Wing crossover series that is actually plausible. I'm a sucker for well-written crossovers.
So go and give