comicbookguy
Super Freak
I think it can also boil down to "why do you collect?". If it's solely for rarity and resale vaule then yes, go ex only. If it's because you love the pieces and value is just an added bonus then buy the ex you really like and the regulars if you don't like or care about a particular ex.
Most people love the Thor PF ex. I actually prefer the regular head on that one so I wouldnt pay more for the ex.
yeppie! I love the ex because it's more rare, comes with an extra part, and if I do sell I won't lose much money. Not always true but still a nice extra.