I don't understand, PCIe has been around for a long time and it will still be around for a number of years so what exactly could your motherboard do to limit your future options?
I'm not saying you should get a crap mobo, I'm just saying you could make it work and if you had to choose between getting a slightly worse mobo (up to a limit) for a slightly better gfx card.
For me there are only 2 real performance upgrade paths for a PC, RAM and Gfx. As long as your mobo has a 16x PCIe slot (don't they all?) then you are good for the foreseeable future since there has been nothing to suggest this will change. That leaves RAM as you major concern and those issue were correctly highlight in the article.
I don't consider your CPU as upgradeable as I've mentioned before, in fact the last time I can even remember upgrading my CPU was when I went from a P3 333MHz to a 500MHz model (iirc). I just always find by the time your CPU needs upgrading the technology has changed and you need a new mobo/cpu/ram anyway.