Which VENICE neighborhood?

We enjoyed staying in Cannaregio and were there for two weeks. Easy to get to other neighborhoods but away from the tourist hordes. Nice armosphere.

I recommend more time, at least four nights.

If you can add a day or two, do so. Be aware that the closer to Christmas, some sites may close earlier than usual. The neighborhoods you listed are all fine. My favorite is the Dorsoduro near the Accedemia bridge.

Cannaregio or Dosoduro have quiet, charm and you feel like you are away from the hordes..

If you want to save $$$ stay near the Piazza Roma. or the main train station.
https://www.tripadvisor.com/ShowUserReviews-g187870-d289202-r22012715-Hotel_Antiche_Figure-Venice_Veneto.html

I will second the Dorsoduro (Frari Church) - San Polo area. Cheaper hotels - a break from the crowds, several sites like Frari and San Rocco, better restaurants and food quality for the money. 3 nights is good for Venice. Plus, you are still close to San Marco square and can see it all you want.

I prefer the Castello neighborhood, specifically the part closer to the San Marco and Cannaregio neighborhoods. It's easy to walk to most sights or catch the vaporetto to Murano-Burano, and yet it's far enough away from the main tourist areas to be peaceful. San Polo-Dorsoduro neighborhood would be my second choice, although I personally find it a little less convenient.

I fretted over this on our first trip but after many many trips to Venice, I find it does not matter. I would prefer NOT to be near the train station, but Dorsoduro, San Marco, San Polo have all worked for us. You can walk from one end of the city to the other in under 30 minutes.

All will work. The historical center of Venice is small enough that you can walk from one place to the next in a short time.
San Marco hotels tend to be more expensive due to the proximity of the homonymous Piazza.

We've stayed in the San Polo area all 4 of our visits (3 at the same B&B)...only a few vaporetto stops from Rialto, or not too long a walk...

We stayed in Cannaregio last month in an apartment overlooking a canal. It was a 10 minute walk to the train station and to the vaporetto. It is easy enough to get to any site you want to see and riding on the Grand Canal to get there is certainly not hard to take. We wanted to be in an area with locals to get a sense of the life there and then do the usual tourist stuff. If you decide to stay there, I would suggest you learn basic Italian, directions, questions, etc. since the locals either couldn't or wouldn't speak English. I was glad I did and it made the stay more fun. I don't know about hotels or the other areas but I would chose to do it that way again. Regardless where you stay I will tell you that when we arrived at St. Mark's Square at 8:30 AM it was empty and we had the Doge's Palace to ourselves. By 10:30 it was a mob scene. Also took Rick Steve's audio Grand Canal tour from the train station in the early evening and thoroughly enjoyed it (minus his Volare rendition- sorry Rick). The Square was almost empty and when we walked to Rialto Bridge the Bridge was not crowded at all.

has anyone stayed in Giudecca?? it seems far removed...but maybe nice?

The problem with staying in the Giudecca is you will spend considerable time going back and forth via vaporetto for everything: every sight, most meals, etc. It is not as charming as staying overnight in the main islands.

Got confused, between Giudecca and Jewish Ghetto.

You can't walk to Guidecca because it's an island. Don't waste your time there. It's not a bad place, but it does involve some sort of water transportation EVERY time you want to see the site of Venice. The Hilton Molino Stucky hotel is on Guidecca and even though it's an extremely nice hotel with a private boat to transport you back and forth across the canal to Venice - you still waste time.