I am currently having my blog updated as well. I just shopped around for about a month and I was recommended to
Blog Designs by Sheila. Well, within one day of contact and partial payment she has already began and is doing a great job with what I explained I wanted. She is very, very cost effective compared to some. Hope this helps.
I used LeeLou for my blog and they did a great job. I used a free template and they customized the header for me and made a Twitter background to match. You can check out the design at http://mybabyfaves.blogspot.com.
It is very personal, you should find a designer that can reflect your style. The look of your blog is really important. Take a look a quirkybird , they designed my website, I am sure they work in blogs too.
I play around and do everything my self. I also have a great friend who gives constructive input who does a lot on the web as well. I use apple software, dreamweaver and photoshop. and countless free resources on the internet.