What program should I use?

I have these ideas that pop into my head that I try to put on paper, but I can't draw that well so I would like to use a 3D modeling Program to make it easier. I come up with ideas for spaceships,items,rooms,vehicles ect.... What would be best for this.

Please advise

Next thread that probably become a talking that none program is the best. If you need free soft then Blender would fit you. In the other way I can propose you 3DS max, but that's just because I like it. Same things you can do in other programs of this kind. Read about them and choose the one with specifications that fits you most

I am exactly just like you, having a lots of ideas but can visualized it good enough yet. usually i use photoshop to cut and paste certain image to get a grip of what i want

this is what you should do.
1: improve you drawing skills
2: download 3ds Max (if your ideas involve organismes then zbrush too)
3: learn 3ds max (and zbrush)
4: tadaa. within 4 weeks you will have very good results

I would use 3D's Max! I think that it would work great for what you want to build!