Once in the hole, I suggest pushing towards 61 and then banking up om AAs then if you want. The hole gives ridiculously great AAxp (and even reg exp). Another place that no one has mentioned is Acrylia Caverns. Not grest exp past 50, but at 55-59 you can bring some serious AAs due to mob density vs mob health
If you're not familiar with the hole... Once in paineel drop down the big hole and that zones you in. You land in water. Get out of the water and go over to a cluster of large stones. One of those stones you can click to open a secret door. There are a couples spawns on the other side that usually agro and open the door as they come to attack you. From there the path is pretty simple. At the first direction choice if you go right it leads to easier / lower level mobs. To the left is the temple with higher level mobs and a little more dense. That area is great for vendor items and xp/aa up to 72. After that I suggest wall of slaughter up to about 80. My box set just hit 80/81 in WoS yesterday and mobs on one half of the map turned green while the other half remained light blue. Loot isn't as good as the hole but mobs don't hit horribly hard if you have a decent aa count and your defensive aas. I'm sure there are other good zones in that level range but after trying a few I decided on WoS due to the pure amount of static mobs all ripe for the picking.
