Whizbang Dustyboots
Gnometown Hero
If there's a race easier to integrate into ongoing campaigns than the Changeling, I'd like to see it. Honestly, even if you just use them as monsters, they make a great addition, especially as dopplegangers are too powerful for many uses of actual dopplegangers in games. (A doppleganger replacing someone in a low-level party can kill every single one of them if discovered, even if he's surrounded.) Changelings, especially as used in Eberron -- the descendants of true dopplegangers with whom they have little or no contact -- are a great replacement.
Their powers are awfully subtle and really not any more imbalancing in play than a well-played illusionist would be. I'd love to play a changeling and never tell my group, in fact, just to see how long I could pull it off.
And, of course, changelings are able to take the warshaper PrC from Complete Warrior, making them a fairly flavorful combatant in return for five levels of play.
Their powers are awfully subtle and really not any more imbalancing in play than a well-played illusionist would be. I'd love to play a changeling and never tell my group, in fact, just to see how long I could pull it off.
And, of course, changelings are able to take the warshaper PrC from Complete Warrior, making them a fairly flavorful combatant in return for five levels of play.