I'm on blogspot myself...but use wordpress for my Alumni Association website. and I lke them both. I think you should toy with both...try the blogspot for a while and then maybe if u like what u really see in word press, import into that. It's a risk but it might be worth it.
I love Wordpress! I started out on TypePad but the switch a while ago has been well worth it and made things a lot easier on me. As far as graphic design goes I went with Girly Blog Designz Heather is great at what she does! I think she only works in Wordpress though.
If you are serious about blogging I would absolutely recommend moving your blog from Blogger/Blogspot to Wordpress. If you're super serious... then you should consider purchasing a hosting package from a host like BlueHost.com and moving your blog to Wordpress.org. Utilizing Wordpress.org allows you to legally post advertising on your site, have control over the CSS and even make your blog function like a website with navigation and all. I do freelance graphic design on the side... please let me know if I can be of help to you!