If you prefer to keep your fingers on the keyboard and away from mice or trackpads, MercuryMover will allow you to do something simple: move and resize windows with the keyboard. There are a number of hotkeys for wiggling the windows into place, in 2 different increments, and a method of resizing windows via the keyboard.
Highbrow gives you fine control over which browser opens a certain link. For example, if someone sends you a link in IM and you want to open in it Firefox, but your default browser is Safari, you'd have to copy/paste that link into Firefox, or Safari will open it instead. But with Highbrow, you can quickly choose which browser opens what. Instead of mucking around in Safari prefs, Highbrow sets the default browser via handy menu bar item. Plus, you can opt for a floating window each time you click a link, and choose on the fly.
MercuryMover is $20 and a free trial is available. Highbrow is $12 and a free trial is also available.