If you can possibly find a real shoe store in your area - not a discount place or payless, but a good athletic shoe store or a place like Abbadabbas - go there and have your feet professionally measured. It's not really the brand of shoe nearly as much as getting one that fits right and is made to support the way you walk/run.
For example, I always thought I wore a size 8. But after being properly fitted, I find I wear a 7 or 7.5 depending on the shoe and that I *need* a shoe that is designed to support my arch because I pronate when I run (that means I tend to place my weight on the inside of my feet, or roll my feet onto the arch).
The last 2 pairs of shoes I had were awesome because they fit right and supported my feet - one was a pair of Mizunos and my newest one is a pair of Nikes. No more sore knees from a bad stride!
I really really recommend getting your feet properly measured and fitted. It makes a HUGE difference.