Since quite a while I do have the following setup: I own a desktop that has plenty of power and RAM. And then I own a laptop, that is way weaker, and where the emphasis is on low power usage, and thus longer battery hours. I use the laptop when I leave the house (I use it on the train, and I sometimes take it to friends if I stay over night, and I always took it to university), or when I absolutely do not feel like sitting at a desk. Because of the less powerful setup, I will not use some of the applications I use on my desktop, or I will use them more rarely.

I think you could get a not-so-powerful laptop coupled with a good PC for the price of a laptop that is as strong as the PC would be. And gain power and flexibility at the same time.