Maybe too late, but here's my answer

Quote Originally Posted by Joshas
I'm still exploring some "new" formats like COLLADA and x3d as they are open, and likely it would be quite easy to write the loader in pascal.
I initially hoped to find something like Quake map editor, where you can easily build whole level geometry, texture it and place entities (enemies, items, lights, etc.) easily in WYSIWYG way.
Blender is WYSIWYG 3d models editor that let's you export your models to many different formats, including x3d (or it's older versions, VRML 1.0 and 2.0). And Wavefront OBJ, and 3DS too. It's open-source, and this is what I use.

But note that implementing full x3d/VRML support in your engine is not trivial, I would suggest to start with some simpler format like Wavefront OBJ or indeed 3DS.