Get one of those high efficiency fridges, they're great for keeping your food cold, and if you can't think of a fun application for that you're not thinkng.
You might want to check the SEER rating on your central air conditioner, they have SEER 18 units available, would cost half as much to cool your home as with an old seer9 unit, could save you a lot of money in the long run.
Check insulation, get more if possible.
Replace all incandescent lighting with compact flourescent lights. You can find them in bulk on ebay, get 100W equivalents or higher.
For that matter you can contact all the car companies, describe the characteristics of the car you want, and ask them to let you know when it's available in a 65+mpg e85 burning variety or 90+mpg biodiesel. Impy that you intend to replace your whole fleet of vehicles when those specs become available from whichever manufacturer offers the lower price.
Find out if it would be economical to purchase a solar electric system. This varies greatly by region, but if the payback period is 10 years or less then you could eventually triple your initial investment.
While your at it, buy a DVD movie and order a pizza. I'd probably do that if I had $xn,000 where either x, n, or both were greater than 0.
Some people with money go to fancy restaurants, like taco bell and even pizza hut.
You could afford to buy real butter and use it to bake your wife some cookies and brownies.
Get a mushroom growing kit and grow your own mushrooms.
You could get one of those robot vacuums, like the roomba, from amazon.com or other vendor. Post a review here in off topic.
I shouldn't have to say this one, but buy your wife flowers every time you go to the store as long as you can afford it.
If your wife wants a puppy, now is a good time to adopt from the humane society or other shelter that neuters/spays all their animals. Buy a year's worth of heartworm preventative from your vet.
Put some of it into an "I'm gonna build a water cooled quad core overclocked sucka" fund, but wait till those quad core processors come out to use it, judging by the photo you already have all the computer you can use.
merlocka: I wish I had an extra slice of cheese.