I'm currently at college. I run my full desktop system and a 19" LCD screen (like I could fit a CRT in the dorm... haha) in my dorm. Space isn't a problem if you can organize some, (and you'll have to learn to organize well to fit into a dorm anyway) (full desktop system means 5.1 surround speakers, 19" screen, full sized tower case, and a 1000VA 600W UPS, along with keyboard/mouse)
It all comes down to what you want, but I'd be surprised if a laptop would be able to last for the next 2+ years for games. especially with DX10 out now. Also, if you get a massive laptop like that the battery life if going to suck. desktop replacement laptops in my opinion are just for the smaller size, you basically have to have them plugged in all the time. Plus laptops are expensive to upgrade, if its even possible.
Also, realize that if you are going to be living with a roommate then he/she might not always lock the door, I've come back too many times finding the door partly open and no one inside or unlocked. If I had a 4K laptop that would not be something I'd want to have to worry about. (make sure to get renter's insurance or make sure your parents policy covers it)
My suggestion is to get a desktop, one that will be for power usage, and a nice light laptop with excellent battery life so that you can go places and are not stuck using the lappy to where there is a plug. If your school requires one, find out why. If you need to drag it to class everyday, that 8-10lbs is going to be alot of weight, especially ontop of textbooks and such.
If the school requires a lappy then I'm betting that they will be used in the class rooms, with no guarantee that there will be a plug in each room (for everyone). Having a desktop replacement laptop that only has an 1hr or so, (if your lucky), of power would be fun if you had multiple classes back to back. There are external power packs. Like this one recommended by Patrick Norton, Electrovaya PowerPad Battery
. He has the 160 series. I don't know what dl.tv episode he recommended it in though, within the last 20 eps though.... But these would give you all-day power, and are nothing compared to the cost of the laptop you are looking at.
Again, its all up to you, but I would recommend a desktop, (you can get the mini case ones that dell/hp have), and a light laptop with great battery life.
Edit -- I also had my xbox, fridge, microwave, and tv (which is not a flat), in the dorm room. Plus I was sharing with another kid who had a fridge and all computer, and all sorts of other stuff as well. You'll be surprised at how much stuff you can really hit in, (just use vertical space (i.e. we had two fridges stacked on top of each other, then my tv on top of that))
Edit2 -- If you are set on a high-performance laptop, look into Acer, HP, Systemax, along with what you recommended above. I won't buy dell, but thats just my choice If you are set on spending $4K on a laptop, just go ask for the most expensive one. I'm sure you can find cheaper laptops that are better deals for the money.