Which one will deliver more Google PR and more traffic to your blog? Now I realize the blog cannot do all the work and you must promote it. But which one will give you more of a 'head start' so to speak.
cant really speak for blogger because i've never given it a go. but if you host your own wordpress blog then you can add plugins for all your SEO stuff - meta tags, automatic sitemaps, blah blah. and its open source too, so you can change everything on it.
if you are just going to use them out of the box then they are probably both okay. but if you want to think long term then you should look at how easy it is to add and change stuff.
I agree with londrum. Although I haven't used Blogger, most hosted solutions hit the wall if you want to start hacking the code or installing odd plugins.
Many hosts have a one-button install that does everything for you in the installation phase, including creating the database and properly connecting it. Once it is installed, you can hack it as much as you want.
Even if your host doesn't have setup automation, Wordpress is usually a super-easy install. Create a MySQL database, upload the WP files, edit the configuration file so it hooks up the database, and you are ready to roll.