Oblivion always crashes on exit. That wouldn't normally be a problem, except that some of the video options aren't defaulting to what I want, and one of them (texture size) can't be changed without a successfull shutdown and restart of the game. I'd like to be able to use Large texture size, and turn on water ripples and reflections. Does anyone have these values set successfully? I think it's just a matter of editing the settings file (.ini), so if I could see what the settings looked like for someone that had those values set, I could set them via editing. Or does anyone know if there is some detailed write-up on the .ini file, and what the different properties mean? Thanks in advance for any help.

The crashes on exit are common and believed to be caused for poor memory management and really are more an annoyance than a issue. This case of trying modify options is one of the issues, since the crash occurs before the disk cash is write.

The solution to this is opening the console and typing (press ~ key or the lefter key above TAB)

saveini

this will force the Oblivion.ini file to be wrote with the current options.

I'll give that a shot. Thanks.
I did find some tweaking guides that addressed some of these options, but I could not find one that mentioned how to set it for large textures. Someone else had asked the same question on another forum, but I did not find a response.

Directly editing Oblivion.ini have pros and cons. The pros are for giving a wide range of control, the cons are where this can malfunction some mods or have the values reseted by these mods.
Since you are seeking ways to enhance graphics at high values I assume you have a rig that can manage this.
But I advise you go light at some specs, Oblivion is very demanding at this settings, with high resolutions and graphics, any thing less then high video cards in SLI or crossfire will scream very poor performance. Where a bit, almost imperceptible loss quality will render it warp speed.