Morrowind:Nerano Manor Key

Quick Walkthrough
# Chat with Sugar-Lips Habasi about jobs and Nerano Manor.
# Acquire a key to Nerano Manor from Ondres Nerano or Sovor Trandel.
# Give the key to Sugar-Lips Habasi to complete the quest and receive your reward.

Detailed Walkthrough
Job
Sugar-Lips Habasi in Balmora's South Wall Cornerclub asks you to acquire the key to Nerano Manor. There are two copies, one held by Ondres Nerano in the manor itself (he is downstairs but the key opens the upstairs), and his servant Sovor Trandel, who hangs out at the Council Club (near the Silt Strider).

Obtaining the Key
The cleanest (although often hardest) way to acquire the key is to Pickpocket it from one of them. You may want to save so you can reload until you succeed.

Alternately, you can kill Sovor (ideally by Taunt or Frenzy to get him to attack you, so you don't get a bounty). He is fully expendable, and if you're also doing Larrius Varro's quest (talk to him at Moonmoth Legion Fort to start it), you're supposed to kill him anyway. 

If you raise his Disposition to 70 or higher, a Nerano Manor topic will appear; using it will cause him to ask for a little compensation, and it will update your journal. If you successfully bribe again (any amount), he will give you the key.

In the unpatched version of the game, another way is to attack Ondres with Hand-to-hand. His skill at it is very low, and he is easily beaten. Once he goes down, you can take the key from him. In the patched game, trying to steal from an unconscious character no longer works.

If you kill Ondres, you'll still be able to complete the quest. However, Habasi angrily takes the key without paying you because now the house won't have any new valuables in it for a long, long time.

Complete the Quest
Once you have the key be sure to clear out the Manor yourself before returning to Habasi. She'll pay you 500 gold for the key, and that's in addition to anything you already took from the house.

Notes
If you've activated Larrius Varro's quest, the other patrons – all of whom along with Sovor are members of the Camonna Tong – will attack when you fight Sovor, so you may have quite a bar fight on your hands. If this happens just grab the key and high-tail it out of there, you can return to kill the others later.
If you are a member of House Redoran, you will be asked to duel Ondres.  If you kill him in this duel, you will be penalized by the Thieves Guild, but Ondres will give up if you knock him out or his health drops below 50.
If Ondres dies during the quest, Habasi is annoyed because it makes her task "very hard". You get the Thieves Guild reputation increase, but not the gold or disposition bump.
If you get the key by bribing, you can return it to Ondres Nerano and receive ten gold as well as a Disposition increase.  Ondres gets pretty mad and "will deal" with Sovor Trandel.  Sovor will no longer be at the Council Club making it impossible to complete Larrius Varro's quest.  If you go back to Sugar-Lips Habasi empty handed, she'll yell at you and send you back to get an extra key.  Of course now you will have to pickpocket it.
If you bribe Sovor Trandel for the key, you can get another copy of the key if/when you kill him for Larrius Varro.
If you are short on gold with which to bribe Sovor, note that he will buy books from you.
You can also increase Sovor's Disposition by successfully trading with him. Sovor buys books and Paper items, which means you can repeatedly buy his Provinces of Tamriel for 1 gold piece, then sell it back for the same value. You can get his Disposition to 70 fairly quickly and save up on the gold that would otherwise be required to bribe him to that point.
Regardless of how you get the key from Sovor, it might be a good idea to pay a visit to Nerano Manor and "liberate" what you can from it before having to return the key to Sugar-Lips Habasi. While it's not necessary to   the side entrance as one can enter through the front door, the key will   the upstairs bedroom door, where one can find various pieces of Expensive Clothing and Exquisite Clothing, several beverages and gold, although some can only be acquired with a higher proficiency in Security.
Each time you say No, nevermind when Habasi asks for the key, her disposition drops by 10.
Bugs
 

Quest Stages