another question. What happens when the size of all your textures goes over the limit of your graphics card? I've got an 8mb card and I am unfortuanately right on that limit. I just added a rather large stars texture and my frame rate slowed to a crawl. Would this be what you'd expect to happen?

Yep.

OpenGL manages this for you — if all the textures won't fit into VRAM, it pages them in when it needs to draw them. Unfortunately, paging is slow, and it'll always page whole textures.

You may be able to get better performance by using the texture priority stuff, but that's probably only a short-term solution by the sounds of it.

You will get a good boost from going down to 16-bit color.