More words easily confused:
rein and reign. I see these confused so often that I've sometimes gotten confused about them myself, thinking there's a misuse where there isn't. A rein is a cord used to control an animal; a reign is the period in which a ruler rules. Thus, when terror rules the streets, it's a reign of terror, and when someone is in charge of a government they reign but they hold the reins of power.
wangle and wrangle. To wangle something is to acquire it (same as finagle); to wrangle is to argue or fight, or to herd (as a wrangler does). Though the dictionary now says that wrangle can also mean wangle. <prescriptivist>Wimps. Giving in to the forces of linguistic change. Hmph. </prescriptivist>
dangle and dandle. To dandle someone is, basically, to bounce them on your knee. There's no such thing as dangling someone on your knee. You can dangle someone from your knee, but only if your knee is horizontal and well off the ground; someone who is dangling is below the thing they're dangling from.
vanquish and banish. To vanquish is to defeat; it doesn't have connotations of pushing someone out of an area.
There was another one I ran into recently, but I'm blanking.