I think you'll be just fine with the base model of the MBP 13". Having a desktop and a laptop is just overkill and not really convenient. It's good to have all your files on one device (though don't forget backups).
Though if you are just about to start engineering, I seriously doubt the use of purchasing a 1k+ laptop right now... Seriously, you don't need it yet, you first gotta prove yourself in the first year and most of the stuff is still pretty general, atleast that's the situation over here... For my first year I had enough with a 10" netbook running OSX (costed me 400), did everything perfectly and I sold it again with only 100 loss and now I bought the brand new model, so happy I didn't buy my Macbook (Pro) last year... I would have so regretted it.
But hey, if you have too much money, go wild I guess. Otherwise I'd say stick with the Dell for one more year and if your studies go well, spend your money on a mac next year.
Good suggestions. The base model doesn't make sense because of the 2GB RAM. I will probably elect for the higher end model 13".
I also have a 160GB USB External HDD that I will most certainly perform frequent backups on.
I also think you're right, I get the feeling CAD software and such will not be used that much while the first year is mostly academia with Calc, english, and such. I may consider getting the Mac next year, but I really am becoming frustrated with this dell, right now, my lap is sweating from the temperature.