Mobility and power would be nice. As far as price range, I honestly don't think it will matter. If it's a great laptop, I can pretty much talk my way into any deal with my dad.
I'm going to college for pre-med, I doubt any engineering programs will be on my laptop, although I use them in school now, such as AutoCad or Inventor. Photoshop will be considered, but I don't think I'll have much time to enjoy those programs.
I'd rather not build my own laptop, I can modify easy with my dad, but if it comes well equipped, I would prefer that. I'll most likely have an external hard drive seeing as I use them now.
Thanks for helping so far!