I just reinstalled Oblivion and some mods.
The game crashes every time I approach the junction of the Red ring road and the Blue road to Cheydinhal, from any direction.
It also crashed when I tried to exit the north gate of Choral when I had the XUL mod for Choral surroundings activated. It stopped crashing when I deactivated that mod.
I love the XUL scenery mods; they make the game much more interesting and colorful.
I have used them before without any problem and don't understand why they would be giving me trouble now that I've reinstalled everything. I feel I'm missing something, but don't know what.
The mods are (in loading order):
Unofficial Oblivion Patch
UOPs additional changes
Cheydinhal Petshop
KOTN
Living Economy
DLC Shivering Isles
Harvest Flora
XUL Patch
and various XUL scenery mods (not all of them)
Any ideas?

The first thing I would recommend is to make sure you have all of the mod's Meshes, Sounds and Textures installed correctly.