If you don't have anything significant to say, don't say anything at all.
Sure, it's important to update regularly especially if you're working to develop a following for your blog, but if you don't have timely, interesting information to present then what is the point in writing? It's the same idea as news releases - if you don't have timely, interesting information then nobody is going to cover your story.
I'm definitely excited about the semester though, and plan to post regularly about what is going on in my classes. I have a full load of 15 hours - Public Relations Campaigns, Journalism & Mass Communication Law, Rhetoric & Pop Culture, Strategic Management, and Entrepreneurship. I'm also planning to either intern or work for UGA's Creative Consultants (a student run PR firm), and am working two jobs - so it's going to be a busy last semester!