Possible phase 2:

Delete questions with score <= 0, no accepted answer and no answers with score >= 0 after three months

If I did my query right, this is about 44,000 questions, which seems like too high to me (as in, not an accurate count.  Are things really that bad?).  Deleting this many would definitely have to be considered very carefully.

http://odata.stackexchange.com/stackoverflow/s/609/qs-with-no-as-0-after-three-months