I want to make a blog about my selective breeding of wild guppies. I want to include pictures and journal-ish entries. I want to be able to categorize posts by month posted, along with content-tagging. I want it to look nice, with a banner and also with a horizontal navigation bar up top for major tagging categories.

Also oh god am I web-design-dumb. Something easy and intuitive, or with a good guide, is also preferred. I would rather not use Tumblr. In addition, it would have to be free, perhaps with aquarium-specific ads (though preferably no ads).

So, what are some good blog hosts?