I'll be honest, like it's been said before, Hexxit is not a huge player map. It's a pack that should be played with 1-4 close friends at most. Otherwise you just have a basic vanilla server with ores everywhere since all the dungeons have been cleared.
On a fun note, I highly suggest when in a dungeon, not to destroy any mob spawners. Especially in the towers, having mob spawners at each level makes it a lot more intense, especially when there's a golem at the top and the tower comes crashing down, running down the tower with mobs still there add to the awesomeness of the event. Plus, more exp!
The only mod that gave me trouble is the more bows mod. It's really awesome and I wish it worked great, but the Nether Bow /always/ crashes my server when it shoots. The mod itself I cannot add to any other mod pack like tekkit either; it makes tekkit stop responding when it's loading and the console isn't showing anything new being loaded.