To follow up on the situation, in case someone else runs into a similar snag, and this might actually apply to people who don't use only the nVidia GeForce 6800 videa card, as this probably applies to many similarly constructed cards:
Dave made the suggestion to set my video card to enable hardware acceleration (which is commonly suggested to be disabled if experiencing difficulty properly displaying visual styles... but seeing as how that's how I had it set, and I had crappy visual style performance, I figured I had nothing to lose
) and instead of using the defaulted Direct 3D driver, to use OpenGL.
I used the default values it gave me:
Geometry Accelation ON
Smooth Line Display: OFF
Gooch Hardware Shader: ON
Full shadow display: OFF
Texture Compression: OFF
The rest I left to previous settings whether they were default, or slightly changed to suit my machine.
In addition to these Autocad particular settings, Dave suggested that I alter some of the video card settings, accessed by clicking the "Advanced" button on the "Settings" tab of the Windows Display Properties dialogue.
On the "GeForce 6800" tab, with the "Performance & Quality" tab active, via the left hand flyout, the lowest check box named "Application-controlled" on the Vertical Sync settings was unchecked (previously was checked) and forced settings "Off". I should note that though the box was previously checked, the greyed-slider was set to 'off' before hand, but to make sure it was as suggested, I forced it manually, for assurance sake.
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Given these changes, I've had not a single lock-up during 3dclip, print preview, or any related problems. I've had one hang-up on a 3drotate command, but it was single, isolated, and I believe it to be one of those normal Autocad hissy fit scenarios where I may have been going a bit fast for it to keep pace with some of it's processes.
Conceptual visual style clicked on in a snap. I've never had it go like this before. It's not an extravagant amount, but the biggest bonus for me, is that before now, it had trouble figuring out what face to show on top of others... i'd have background pieces showing on top of others, and faces distorted and such. Now it's showing quite accurately with only minor problems that seem typical.
Realistic visual style works 100% fine. I have materials and textures applied to the model, multiple xrefs, 3d and 2d geometry. Does regen slightly slow, but I think it is of an ordinary amount because of textures/materials. A switch to a copy of "realistic" that does not show textures made it a little faster.
Overall it's actually improved performance and efficiency in almost every area, and if it didn't improve, it remained unchanged.
Quite a tip from Dave W! Thank you so much, again!
