As another DCA-based flyer, I would recommend AS. Getting Gold on AS is no harder than getting Gold on UA if you are using AA and DL which you probably will. MVPGold does give you a chance at an upgrade on DL, although it has only happened about 10-20% of the time for me. AS miles will be great for redeeming to the destinations you list.

Don't forget that you will also earn EQM on EK, AF, and KLM, so taking a paid flight to one of your vacation spots may net you the status you want. I redeemed 100k AS miles to fly the wife from DCA to MNL last Feb. on CP in business and she said it was great.