Combating (or combatting)
Traveling (or travelling)
Grrr. This is irritating to me, not only because you can spell it correctly both ways, but because the "preferred" way spell both of these words is in opposition to the generally accepted rules about spelling (you remember, the rules about adding a suffix to a word ending in a vowel-consonant?). If we're going to have rules on spelling can we at least try to be consistent, folks?
Oh, by the way, this is another thing I do when I'm bored - ponder the idiosyncrasies of the English language.
A mind - it's a terrible thing to waste.