I picked up a butternut squash yesterday at the supermarket, not sure what direction I was going to go with it. Not quite feeling like a soup today, we decided to do the traditional baked - splitting it length-wise, seasoning with butter, nutmeg, cinnamon and brown sugar. To give it a little kick, I threw in a bit of vanilla extract. Worked great...even my 5 year old loved it! Next time I plan to get some toasted pecans in the mix.
I tend to follow the baking instructions that come with the squash. There should be a sticker on the squash with both baking and microwave instructions - the microwave option actually works very well and only takes about 8-10 minutes.
Here's a link to a basic butternut squash recipe that would work well. I just added my own favorite fall spices to the mix.