Where can I buy good looking, unenchanted apparel?

I'd like to buy good looking unenchanted apparel and then enchant it myself.

Where are the main vendors for cloth apparel, necklaces, and rings?

Radiant Raiment in Solitude sells many many different styles of clothing, ranging from ragged clothes all the way up to the more expensive fine clothes.

They also sell jewelry, although your best bet for making the best jewelry (except for circlets) is crafting them yourself via smithing.

When completing the dark brotherhood quest line you can get hold of emperor clothing. Worth 100. Looks good. Also wedding clothing can be taken from the bride following the same quest line.