4 MUST have add-ons!!

AreoHotah

1. Advanced Filters
http://www.esoui.com/downloads/info245-AdvancedFilters.html

What it does it creates new undertabs in both your inventory and bank for specific items. For example under the Materials tab it creates undertabs for Enchanting, Alchemy, Provisioning, Clothing, etc. That way when you search for that specific item you don't have to go through dozens of mixed up mats. A must.

2.Banker
http://www.esoui.com/downloads/info362-Banker.html

This one is very usefull for cleaning out your inventory in just a few seconds. Automatically transfers already stored items in your bank. You can also configure exactly the items you want to be stored automatically. This is specificaly for those that whined that the ''inventory is unmanagable''

3.AI research grid
http://www.esoui.com/downloads/info265-AIResearchGrid.html

Allows you to quickly and easily see which traits you have researched for Blacksmithing, Clothing & Woodworking, wherever you are in the world. Very usefull if you sell and buy traits. Saves alot of time by not having to run back to city.

4.Merchants
http://www.esoui.com/downloads/info151-Merchants.html

It shows EXACTLY where merchants are in town. How many times have you searched the entire market for the bag upgrade guy?? :P not anymore.

Hope it helps. Cheers.

Uzkul

I only use the AI Research Grid one of the ones you listed.
Though I just downloaded Advanced Filters as well.

If I may, I would add some others I found most useful.

CraftCompare
http://www.esoui.com/downloads/info231-CraftCompare.html
Shows you your current item equipped when you crafting/deconstructing/improving another item.
This way you can see immediately how the new item (or item you're improving or deconstructing) relates to your current equipment. Can it be safely deconstructed? Is it better then what I'm wearing now?
Saved me quite some time already.

Dustman
http://www.esoui.com/downloads/info97-Dustman.html
Or any other addon that automatically vendors trash when visiting a shop.

Inventory Grid View
http://www.esoui.com/downloads/info65-InventoryGridView.html
From the same guy that made Advanced Filters.
Slims down your inventory to icons, so you don't have to scroll like a madman when trying to find something.

Item Saver
http://www.esoui.com/downloads/info300-ItemSaver.html
Again from ingeniousclown as well (Inventory Grid View & Advanced Filters).
Mark items you want to save so you don't accidently deconstruct them or sell them.
I specifically use this to mark items I need for researching.

Paks_ESO

Fast Report: http://www.esoui.com/downloads/info181-FastReport.html

Easily report those pesky bots and ruin a gold seller/farmer's day.

cjmarsh725b14_ESO

BatmanStoreFilter
Creates more filters under the Materials tab in the guild store, making it a whole lot easier to search for specific items in trade guilds.

SkyShards
This puts icons on your map with the locations of skyshards and they also show up on your compass when you get close to them.

SWAPS
This is a very handy addon that lets you save action bar sets and then switches your entire bar with a single click. You can currently save as many as you like with various icons.

Lootdrop, Continued
This is a simple addon that was picked up after the original author left it. It just shows a simple popup of whatever items you just looted, very nice if you're using auto-loot but still want to see what you're getting.

I didn't include any links because I use Minion which is a simple application you can download at esoui.com to manage and automatically update all these addons.