Either get paid hosting or (personal choice) see if you can manage with wikidot.com. Its an awesome service and their software is highly customisable, and you are even allowed to use own domains for free.
For a simple, neat, feature rich, well supported and high traffic blog, I suggest wordpress.com. You can buy upgrades like custom CSS Editing and own domain name for just 15$ per year.
I use wordpress.com and find it much much better than blogger.com because of the excellent community support and great developers who keep adding more and more features every few weeks. I love its free 3GB webspace but it allows only ODT, PPT, Image, and a few similar file formats for free, unless you purchase an upgrade for 30$ an year which gives you 8GB webspace. All bandwidth is unlimited and they actually encourage submitions to digg.com, slashdot.org, etc.
As for wikidot.com, its a wiki software with great features, and is highly editable and you are allowed to use own themes, domains, etc, and allows you to use its file hosting serivce too for free, but the main and only downside is that you need to learn wiki editing language which wouldn't take more than a few hours of patience to learn.