Would Rotom fall under the 'uber' category??
Also, i remember someone saying that  Regigigas was not an uber? Can someone define where that line is drawn??
I am also looking for an Oval Stone which is used to evolve Happiny or Chansey, im not sure... but it seems there is only one available per game.
Does someone know if its possible to get one from PBR? or from the Battle Tower??
I really want one and am willing to trade an Electirizer (maybe) or one of my TMs like Toxic or Protect or something.
Thanks to whoever takes the time to answer!

First, Rotom is not an uber.  In fact, you can breed with Rotem, although just with Ditto.  "People" decide who is Uber, OU, UU, etc.  They are categories that the "majority" of players agree upon.  I currently use the list on smogon (www.smogon.com).  In reality, an uber is a pokemon who just has too many good stat categories, or such an awesome moveset (mew) that it is broken.

As for an oval stone, that evolves Happiny into Chansey.  If you are breeding Chanseys, they make other Chanseys so you won't need many Oval stones.

Oh, and Regigigas is not an uber.  He's not even that great due to his ability.

Dude, I have quite a few Oval Stones. Like almost every Chansey I catch has one.

Might be nice to get an Earthquake TM for it.