I think HP will work with you on the video card, but don't quote me.
I like having as much hard drive space as possible
It really depends, though, on what you're planning to use the computer for. If you will be saving video or large photos or a lot of audio on it, you will want more space. If it is for gaming or a mega word processor, you won't need as much.
I haven't had problems with my HP screen. It is pretty reflective, and if I have it in the car when it's bright out, I have to arrange it carefully to reduce reflection and glare to see what's "behind" the screen, but in general - and at home - there is no problem.
My HP's battery lasts a couple hours. I use it at church instead of a Bible and notebook, and my son plays games on it, usually, before and after church, and we haven't run out of battery power yet.
I really like my HP.
We do NOT recommend Compaq or Toshiba. Dell's are ok but their support is now outsourced to India.