i'm starting with a little smallville....
Frantic, by Jenn, is future-slash, funny and a little hopeful. Clark's visit home involves sentient kryptonite goo, a slightly manic, rifle-wielding arch-nemisis, one of said arch-nemisis's secret underground lairs, radioactive liquor, and some very hot sex. (slash; Clark/Lex)
RivkaT is one of the best, and Switch, a Comedy of Terrors, is one story of hers that I particularly enjoy. It's a body-swap fic, and after reading this, that definitely became one of my kinks. The characterization in particular is incredibly well done, and I love Lex's scientific-yet-protective response to being in Clark's body - and finding out what it can do. (slash; Clark/Lex)
Freshman Orientation, by Punk, is sweet and hopeful without being at all saccharine. Clark is a freshman in college. Lex is living in Metropolis, and he and Clark are dating. This is where all of that lovely friendship-based UST from the beginning of the series should have gone. The utter normalcy of the events in this story provides a lovely contrast for all of the parts of Clark's life that are not normal at all. (slash; Clark/Lex)
Punk and Tiffany Rawlins co-wrote the next rec, a clark/lex epic of staggering genius. It is beautifully, interestingly written; a series of stolen moments done in a different sort of style that is incredibly interesting to read. It reads like bits and pieces of the most golden sort of summer. (slash; Clark/Lex)
and now some crossover recs...
In the Same Boat, by Mad Poetess, is one of the best crossovers I have ever read. The first line of this story sucked me in, and the language and style are powerful and beautiful and raw. Mad Poetess does a phenomenal job of writing a perfect River-voice. You do need to be familiar with both fandoms to properly appreciate this story.
All the broken things in the 'verse end up on Serenity somehow, and Spike, no matter how hard he tries to deny it, is broken. This is an incredible look at Spike through River's eyes, and her interpretation of their mutual status as outsiders is beautifully actualized. (BtVS/Firefly gen; Spike, River)
Kamikaze, a BtVS/Alias crossover by Lesley, is another worthwhile read, even if the mix of fandoms sounds improbable. It's well-written, with a coherent, developed plot, and the story itself is fun to read. The interaction between Spike and Syd is just plain fun, and of course he reminds her of Sark. You don't need to know much about Alias to understand this story, (BtVS/Alias het; Spike/Sydney)
Daegar's California Dreaming is a Buffy/Good Omens crossover set in season three (buffy) and post-book (good omens). Familiarity with both fandoms is a necessity. Crowley, ordered to return to Hell for an audit of his accounts, is told to travel home via the Hellmouth. The scenes of Crowley loose in America could have come straight from the pens of Pratchett and Gaiman; the encounter between Crowley and the Scooby Gang is perfectly characterized, and the scene at the end in which Crowley has a chat with Willow is quietly chilling.
Daegar, by the way, writes the best Good Omens fic ever. Read all of it. If you don't know what Good Omens is, go buy the book. I'm serious -- go to amazon.com and order it now. You won't regret it. (gen; Crowley/Aziraphale if you squint)
L'Heure Bleu, by Dale Edmonds, has been recc'd all over the place, and with good reason. It's one of the few good HP/BtVS crossovers out there; the pairing is Draco/Riley, and it's just -- it's perfect, is what it is. Both of them are bitter, cast aside survivors of wars that were never theirs to fight. Read it. Now. (HP/BtVS - slash; Draco/Riley) *Link is currently down.*
Nativity, by Milkshake Butterfly, is a Brimstone/Dogma crossover, and it is deeply, deeply funny. You should be familiar with both fandoms to appreciate the story. Eight and a half months after the events in 'Dogma,' there is no room at the Days Inn, and Bethany Sloane must seek refuge in a Wal*Mart. Features three wise nuns - who arrived in a VW bus and carrying a Visa Gold Card. It is, however, the snark between Lucifer and the Metatron, that makes this story the gem it is. (Dogma/Brimstone; gen)
**If you find any broken links, please let me know and I will fix them!
***If I have rec'd your story and you would like me to remove it, let me know and I will do so!