To be fair, all charities have different cost structures. While the Wounded Warrior program doesn't spend more than 1/2 of it's receipts on fundraising, it is indeed pretty high. As Mudflaps link shows, of every dollar brought in, 60 cents goes to the mission purpose. As Spitfiren8 says, there are also other great organizations like the FisherHouse who plow more of your money into support; above 90% for them. I give quite a bit to them and their Walter Reed location. There are a number of places to see the actual numbers. Charities are required to post their Form 990 IRS filing each year and provide for inspection as requested by ANYONE.
Military organizations are a great place to give but nothing beats sitting down and taking some time with a vet and listening and thanking them for their service. It's free and it means a lot to them.
I do like the idea of pinball for service members actually. Could be great in hand eye coordination rehab, distractions from PTSD (although must consult with the professionals on flashing lights), and in the rec centers on base for families. Good idea and hool10... and help make it happen!