What is the best gear for a level 89 balance wizard? I tried several different gear and none of them were the best.
At that level, I remember using the Waterworks hat and robe, Azteca crafted shoes, Wyrd-Oak Staff, Tower of the Helephant ring and athame, and the Sun's Piercing Ray amulet.
Also, if you want more variety than that, level up to 90 so you can try to get the Alpha and Omega ring and the Blade of the Felled Titan athame. Most level 120 people I see still use the Alpha and Omega ring, as it is a really good ring. At 90, you can also farm for the Hades gear, but most people just wait until level 100 to farm Malistaire instead.
If you don't want to farm for Hades or Waterworks gear, then I suggest you get into crafting. The Azteca crafted gear is really good, and at levels 94 and 96, you can equip Khrysalis crafted gear, which is in some cases better than Hades gear.
There are several official W101 fan sites that have a list of gear that you can use for most any level. Honestly, it is up to you to do the research on the internet to find out which works best for you.