Ask HN: Best Wiki and Blog Software to accompany my startup webapp

I'm working on a webapp that will hopefully launch in January / Feb. I'm at the point where I want to incorporate a blog and a wiki. The blog will be a marketing channel where myself and my partner will talk about our product and make announcements. The wiki will be used by the dev team as a sort of project management tool to track progress and dump ideas and will be private. I'd quite like some simple suggestions for the blog tool. Something like wordpress seems like using a sledge hammer to crack a walnut. I'd happily use a 'project management tool' instead of a wiki. What are your experiences ? Can you suggest anything ? Or Should I stay clear of anything ?