Jogging in Washington D.C./Arlington Area?

I just moved from Madison Wisconsin which has a terrific biking/jogging scene - probably one of the best. I used to enjoy several different routes - usually between 5 and 10 miles. I live in the Clarendon area of Arlington now.. only a few blocks from the Arlington National Cemetary. If anybody around the area could offer some advice on some good paved routes or otherwise good neighbors that are safe to trek through (I enjoy running at night especially), that would be great. Thanks.