My condolences at acquiring the Nats. I do actually follow them being a Northern Virginian in a group with season's tickets. I'm sure Todd can provide the answer you want but here are a few that may be on his lists. Some of these guys may have been up for a while this season but realistically they are minor leaguers.
Here is a link to the Nats farm page:
http://natsfarm.com/
The NFA Big Board [all players in their system] spreadsheet is here and can be found on that page:
http://spreadsheets.google.com/pub?key= ... utput=html
Stephen Strasberg is obvious.
Drew Storen will be their closer in 2011 and maybe 2010.
Shairon Martis is likely of value in 2011
I prefer JD Martin to Detwiler as an eventual starter
They may draft Bryce Harper next year.
Their current position players in the minors are not too good.
I'm not sure if they have any AAA players of value.
In AA, the interesting ones is Marrero - interesting not necessarily good
In high-A is Burgess
Ian Desmond is up right now but I don't know much about him and I don't think he is that highly touted.
The Nats have pretty much drafted pitchers high in their latest three years. Only Jordan Zimmermann appears to be a 1 or 2 type SP and he came up early this year. If he qualifies in your league, he is a keeper.