Given current market conditions, one of the things you should be doing is reviewing any non-registered investments you might have. If you've incurred any taxable capital gains in 2008 or any of the three previous years, it may be time to sell some of those stocks that you're sitting on because they're not doing so well.
Nobody ever wants to lose money on an investment. We tend to sit on our losses because if we don't actually sell the stock we haven't actually lost anything. The problem with this strategy is that if you only sell your winners you end up paying tax and not getting the only benefit of loser stocks - a tax deduction.
If you have any stocks with capital losses - and with what has happened in the last few months that's a real possibility - you can sell them prior to the end of the year and realize the loss. The loss on the loser stocks can be used to offset the gains on your good stocks. On the upside, you can use the money from the loser stocks to buy more of the stocks that are winners.
If you truly believe the stock is going to come back, you can always repurchase the stock. The only catch is that you will have to wait more than 30 days to repurchase. If you repurchase a loser stock within 30 days of selling it, the loss will be deemed to never have happened and you lose the benefit of selling the stock.