These sites are...by far, some of the best Sims sites out there. I've searched high and low for decent anime skins and objects, and other offbeat things that will definitely spice up your game.
Affiliates:
Jrock related:
A nice site with many, many anime skins and jrock skins. Definitely worth a look!
If you want a *beautiful* set of skins for Mana (ex-Malice Mizer), click on the link that says "labels". The best part is...it's still a male skin.
For the most part this site should go in the "others" category, but there is a Kyo head available for download (Go to themes and then "celebrities") body is said to follow. This isn't the only reason to visit the site, however, I LOVE the skins on there, and the Elf project they're currently creating with FrillySims is awesome.
Anime Skins:
BNJxLVR-Definitely one of the sites I've often frequented, BNJxLVR has a wide array of heads and meshes (some meshes which I've used) and awesome japanese objects for your Sims' house. Also check out the old archive for anime skins like Shoujo Kakumei Utena. Definitely one of my favorites.
Shikaku.org-From what I've seen there are not many X skins floating around out there...well, not only does she have Sumeragi Subaru and Sakurazuka Seishirou from X, but she has skins of them, and Hokuto from Tokyo Babylon too (I <3 Tokyo Babylon)
Happy Simz-This site has a lot of anime objects including a Gravitation theme and an X/1999 theme (though I definitely give them props for the anti-relena themed items. ::snickers::). This is where I found the skin of Monou Kotori, as well.
Nachtengel's Sanctum-If you like Weiss Kreuz, you'll love this site, which has all four of the Weiss boys and all four from Schwarz (my only problem is with the Omi skin, which I don't think should have been made with the "fit" body type, but that's just me). Other skins include Nadeisco, Fushigi Yuugi and Rurouni Kenshin.
Spirit World Sims-This site has some really cute skins (I really liked the Lain ones ^-^;) and lots and lots and lots of anime paintings to decorate your Sims' house with.
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This site, well...this site gets stars by it because of three things. 1. They actually have Fruits Basket skins, and the skins are really really cute. 2. It's currently being added to (meaning she's actively working on making new Fruits Basket skins right now. One day..I'm sure there will be Haru 9_9) and 3. The webmistress is nice. Now she's even got Chobits skins. So for all of these reasons I had to put stars by it. And you'd better visit. >.>.
Anime sims central has a LOT of anime skins, some awesome, some good, and some...kind of scary. But definitely a good place to start if you're looking for anime skins.
This site has some really awesome skins to offer, including Chi from Chobits and some skins from FFX.
This site contains some of the best anime skins I have seen, from Shirou Kamui to Belldandy to Heero from Gundam Wing.
Lots of anime skins XD if you're a fan of either CLAMP or Bakuretsu Hunters, I would suggest you check this site out.
Non-anime related:
Frilly Sims-Beautiful meshes and beautiful heads, and if you want something that deviates from the normal children heads then I'd suggest you stop by here. I've used some of their meshes before as well ^-^
Sparkling Sims-These dancing poses are awesome and definitely original XD so if you'd like to display your sim skins as dance-aholics, I suggest you start here.
StarryNightSims-lots of skins and heads available for download, but the part I liked most was the poses, many of which I've used...almost all of which I've DLed x.x;.
I've tried to make poses using simposium but for some reason they never quite look right. This site, however, has a lot of great poses you can use for displaying your skins, many of which I've used on this site.
Just when you thought it was hopeless to find really really nice objects and furniture for your Sims, this site offers some really great stuff.