I'm trying to find the house of the guy who stands in Whiterun preaching to everyone. My quest wants me to get to his house but I can't find it. I've looked everywhere! Does anyone know?
Heimskr's House is close to the Gildergreen tree in the center of Whiterun, very close to the Shrine of Talos where Heimskr preaches during the day. The UESP's map of Skyrim might be useful if you're having trouble finding it.
If you've completed a certain quest:
the Civil War quest "Battle for Whiterun"
his house will have been blocked by debris. In this case, it will be inaccessible permanently.
If you're doing a Thieves' Guild radiant quest, (and I'm pretty sure you are, as this is the only reason to go to his house for a quest) just go back to Vex and quit the quest in this case. You can quit these quests and ask for new ones at any time with no penalty (besides some snarky responses from the questgivers).