Notebooks are designed for portability and are not meant to be used as powerful workstations. Notebooks tend to have slower CPUs to conserve power, with limited RAM, storage and expansion options to keep them light and portable. It's generally a bad idea to carry massive amounts of data in your notebook. You may lose your notebook or customs agents may take away your notebook for inspection (read this).
I don't carry a very powerful notebook; instead, I use remote access with my home PC. With remote access software (like LogMeIn) and 3.5G mobile broadband, I have access to my powerful computer at home, from anywhere in the world.
I use remote access to download and evaluate new software, since the broadband connection at home is much faster and I don't have to worry about messing up my critical work applications on my notebook. I use remote access to run intensive applications that require lots of CPU and RAM, like development tools and video transcoding. I use it for running 64-bit versions of Windows and Linux, which wouldn't even install on my notebook.
From my experience, remote access over 3.5G is perfectly usable for serious work. I don't recommend storing sensitive data on your home PC, but if you need lots of storage and computing power on the go, remote access to your home PC is probably the best approach.