I have a United voucher for a free flight anywhere in the contiguous 48. I have one year to use it. I'd be originating from Washington, DC. Where would I get the most bang for my coupon (and get a fun vacation in the deal)?

California, dude! San Fran, LA, San Diego, you name it.

Oooo, if you've ever wanted to see the Colorado Rockies, take this free flight to Denver. It's as expensive as heck to fly in there now.

California would be a good choice Definitely LA or San Diego would be good choices. You could also fly into San Jose and include a trip to Monterey and down highway 1 (Big Sur, Hearst Castle, Morro Bay, Santa Barbara) and then fly out of LA. That way you can experience bith northern and southern California. I think that would be a excellent trip. Find out if you can use the coupon for a n open jaw ticket (flying into one airport and out of another).

While we have used free miles to fly Boston to West Coast, if there is someplace in between you have wanted to go (like the Denver poster mentioned) go there. Often great advertised deals coast to coast, but the huge middle of the country gets fewer airfare deals.

And if cost upon arrival is an issue, the coasts are usually much more expensive.

We were able to use FF miles several years ago (I know you have a voucher, not miles) to fly into Seattle and out of San Francisco - drove between the 2 - a great trip.