Well, your bang for the buck may vary depending on your goal, but at least that's something to work with.

So, if you're US Airways silver preferred I can assume you've flown 25,000 miles in the last year or two. If that's the case you should look into the Aegean Miles and Bonus program. For the same number of miles you could have Star Alliance Gold status, which you could more easily use for lounge access on your domestic flights.

150k US Air miles is a good start towards a nice honeymoon, but I'm an American Airlines / Oneworld guy so I'm sure someone else is more qualified to advise you on how to spend your points. Any idea of what destination you have in mind? Or at least a continent?