For the buffyversetop5 Fics with Outstanding Characterization:
1- Cuckoo in the Nest
Wow, this fic takes us inside the head of Xander's father: Tony Harris. We get to see Xander's life and the events of canon through the eyes of his father. New idea of a fic, amazing characterization, amazing plotting. I especially liked how she made Tony look like a person and not like how many portray him as Mr. Evil Rapist.
This is one of my favorite season 7 Spuffy fics. All the characters sound in character, the plotline was interesting, the Scoobies' relationships were interesting! We have Buffy dealing with her flaws, I love that it didn't take an "over the top" style to have her discover her weaknesses and flaws. Amazing portrayal of Xander, flawed but still the good man we see on the show. A nice Willow trying hard not to screw up. The grown up Dawn we saw in S7. Anya didn't appear much but she's sarcastic and still blaming Xander for her own choices. As for Spike... well, why don't you read and find out. *winks*
3- Sweet Revenge
A rewrite of season 5 but Spander style. Spike is the character that attracts me the most in this fanfic, usually fanficcers try their hardest to show us how Spike is worthy and deserves to be treated better, sometimes exaggerating to the point of showing him as a saint, even with his apparent flaws. Here though Jackson gives us the real Spike, the Spike who goes through major developments to improve with time for the person he loves without losing what makes him a vampire. I guess the fact that she's using S5 to write her fic helped her to keep Spike in check. Her Spike will always be my favorite Spike.
4- London Calling
If Saint!Spike annoys me in fanfic, then Marty Stu!Xander annoys me even more. Shadowscast writes a wonderful, believable Xander and you can just see it in the first scene of the fic where Xander and Buffy argue over Spike's AR. Some writers go very mellow with Xander sometimes while others make him go over the top with his Spike hate, but her Xander has a mix of each, he hates Spike but will do whatever he can to make Buffy happy. Of course, other than her Xander characterization, her plot is very intriguing and pulls you in. One of the best Spander fanfic.
5- Starting from Nowhere
I'd die for a fic that lacks Riley bashing, so thank you st_salieri
! I'm not into Xander/Riley but you can really believe that Xander has it for Riley, plus this is the only fic to convince me that Riley can, well, be gay with a guy. :)