Personally, as a GM, I find buying lots of stacking powers so that you can never get into a situation where it doesn't work to be sort of a pain -- I won't stop somebody from doing it, but I can usually talk them out of it. A game in which nobody ever has their defenses bypassed because they spent all their points on said defenses isn't fun -- it's fairly boring, actually, unless the GM ups the ante. And I'd rather not up the ante... that results in badness, especially if people in the group do this to different extents.
On the other hand, here's an example of a character I created. She does have some overlap, although at the time, I didn't realize this (she was my first character created):
(Not statted -- no stats with me)
Basically, Super-speed +7 and Evasion, which effectively means "Amazing Save
amage +7" unless she's denied her Dexterity bonus or saving against damage from an Area Effect attack.
On top of that, Energy Field(Cold) with Protection added to the field. The character concept was "Miss Slick, the superheroine who is able to generate a field of cold and move very quickly through an instinctive understanding of the energy source known as
Reverse Friction." The field was at +6.
AS
amage and Protection stack, so that +7 and +6 only went up to +10 -- usually, her field wasn't so strong while she was moving, so the +7 went to AS
and she only benefitted from Protection +3. But if she was denied her Dex bonus due to being flat-footed, she'd lose the +7 and get the full +6 from her Energy Field.
Of course, I also had a character with Strike +7 (Cosmic Power) and Strike +6 (Training), which, because of stacking, only went to +10. He had glowing energy fields around his hands (Strike as a Power Stunt of Energy Blast from his Cosmic Power), and he also had years of battle training. Due to his warrior code of honor, he would at times voluntarily drop his energy field and fight someone hand-to-hand. Not often, mind you, but when he did, it was nice to have +6 instead of +3.
