Agree. If you want better loot definantely Ice Giants. If you want the faster exp you could kill Flesh Crawlers (Level 35, 25 hitpoints) since you don't have to do so much yourself. They are agressive for a long time so you can kill pretty many then use the boney chain back to the start, walk back and they are agressive again. These also just have a max hit of 1 but they sure are fast. The Giant Spiders (Level 50, 51 hitpoints) on the third floor of Stronghold of Security are agressive for a long time too and they are closer to the ladder so you can make them agressive again fast. They have more then double the hitpoints so they are better to kill, though they have a higher max hit. I got a lot of lvls down there but the bad thing about these is that they give no bones, so if you want prayer too the Ice Giants is your spot. Hope this helps :D