There's only 8 more days until Wrath's release. Each day until the release we'll take a look at one thing you can do to prepare for the expansion. Taking a half hour here and there to get things ready before release will let you spend more time in Northrend and less time doing some of the un-fun things.
It might seem a tad strange now, but that big bank of yours is going to be more or less worthless once Wrath hits the streets. Just about everything is going to plummet in value. Liquidate your assets now or be in worse of a position than our real life economy is.
There are some exceptions to that of course. You'll probably want to hang onto enchanting mats, since they can still be useful and high-value in the long run. You might also considering hanging on to some herbs for those leveling inscription. Most other raw minerals however can probably be safely sold now.