Alas, there used to be many more links than this, but some good original Sims sites remain. Here are my favorites.
AponeeSimz: Tons of beautiful, unique objects.
Around the Sims: French and English site with some really beautiful sets, unique themes and hacks.
Cómhair: Really beautiful historical and LotR skins, and some nice object sets.
Dincer Hepguler: Incredibly well-crafted furniture sets, and some unique items (like a helicopter!)
Ess Sims: Lots of neat stuff!
Ferndale Sims: Beautiful plants and build objects.
Madoria's World: Pretty sets, skins, apartment objects, and original bases.
Parsimonious: MANY gorgeous original sets in a variety of styles. Some nice skins and walls as well.
Persimmon Grove: Lovely garden and outdoors things, all EP-free.
The Secret Society of the Woobsha: Several nifty hacking projects, and DIY resources.
The Simarillion: Absolutely stunning Tolkien-themed skins (and some objects).
Simcredible: Snazzy, mostly modern sets.
Simlogical: No longer updated, but chock full of innovative hacks.
The Sims Resource: Paysite, but Sims 1 content is now free. A mixed bag; some stuff is crap, some (like Secret Sims and STPCarly) is truly impressive.
ShinySimThings: My Y!Group, holding miscellaneous stuff that I haven't/won't move over here.
Shiny Things Shared: My other Y!Group, where I post my apartment objects. Some bases too!
Sim Apartments: More apartment stuff.
PollyMogs: Some lovely original objects and base objects.
Sim Dandies: An oldie but goodie -- many beautiful walls and floors.
Neighborhood 99: Sims Central! Updates, file sharing, tips, and random chat.
Simblesse Oblige: Another thriving forum.
SimsOne: For the diehards among us.
Save these buttons to your own web server and link to http://www.simerables.co.nr/. Thanks!