I have a weird thing going on... I went and copied my last map files, deleted some stuff, renamed, fixed shader file and shaderlist, etc. I open GtkRadiant 1.5 (same version I've been using, on XP), and it won't draw any brushes. Even with any other textures. Anybody seen behavior like that before?

Like you make a box and it doesn't show anything?

Yes, I'll try again today (rebooted the box), I ended up working on my wife's machine a bit (no problems there).

Could it be that you are by accident filtering some aspects of the map ? I have no experience with 1.5 but in my 1.4 there is a menu View -> Filter. Look for that and see if any of the listed items are being filtered. You could have pressed Alt-1 by accident which would produce the result you are describing

lol, I are stupid! I discovered this on my own, yes... I was filtering the 'structural' brushes!
OK folks, don't forget to reset your filter views!