When working with WordPress you need to understand that not all themes are created equal. If you want a world-class blog that you can be proud of you have to consider the crawlability and the design of the WordPress theme that you are using. Some of them aren’t worth a dime for SEO.
For instance, on some themes the title may not be completely visible. That’s a problem. Another common problem you can run into is bad CSS. If the code doesn’t allow you to change your color themes then don’t bother with it. It probably has other issues as well.
You can check the code in your WordPress theme but even if it checks out OK you’ll still need to give it a test run to make sure it is usable. Not all problems can be detected before you upload your theme. For instance, some WordPress themes will not allow you to add categories for your links. If you can’t add link categories then it will be difficult to organize your sidebar properly. This is especially true if you plan to have a large sidebar.
Some WordPress themes include malicious code or affiliate code for the designer. You don’t want someone else making a dollar off of your blog every time someone leaves it or visits the designer’s web page. Do you? Some hackers will offer free themes then put in a back door so that they can add link code later for an affiliate that pays them. This is pure evil – black hat all the way – and you don’t want to get involved in something like that.
When you set up your WordPress blog it is best if you choose 5 or 6 themes that you like and rank them according to your favorite. Then you can check them out one by one to see which one is best for SEO purposes. A pretty design is nice, but if it doesn’t allow you to take advantage of the SEO benefits of blogging then being pretty won’t matter.