It wouldn't be a bad flight to upgrade on - at 2080 miles, it's essentially a transcon. If you choose to chance a day-of-departure cash upgrade, I believe it will be $250 per person per direction. Whether that's worth it or not is entirely up to you, but BoeingBoy has provided a good description of what you can expect.

Personally, as close as you are on miles (155k), I'd buy the extra 5k and treat you and your +1 to a business class trip to Europe and not waste them on a domestic/Caribbean flight. Although as cheap as US miles are to acquire right now, you could go for both... Whatever you do, I'd be sure to burn your stash down to zero before the first of January, 2010...