Theme are a very important part of WordPress, with a good theme you will be able to impress your readers, There is a Well Known sentence in Chinese, which translated to English Means, People judge you by the way you dress, and more or less, it applies to blogs also, If your appearance is appealing, you will definitely gain more trust. It must be fast to load and also neat and tidy, remember nobody likes a place where there is simply too many advertisement or pop up screen. Keep your blog neat and tidy.
Appended below are some of my personal favorite theme which I have used or is using now.
http://www.designdisease.com (Evidens Theme)
One of the main advantages of going for a premium theme is the support, When you are a paying customers, they will definitely offer much better support, It won’t be best effort, It will be a must solve issue. Premium themes will also looks nicer and better appeal.