Visit a local bike shop. Find one that will take some time with you. Even if you don't get quite as good a deal on the hardware, the expertise and the help with fitting will be worth it. There are a lot of bikes out there, and the choice can seem overwhelming, but once you've got a bike that fits you, you'll likely be happy with whatever speaks to you. I wouldn't necessarily limit your choice to single speed bikes. Tell the shop what you are planning to do with it (commute, shop). Don't put too much stock in a test ride when you are just looking, because changing stems and saddle position can make such a huge difference in comfort. Fit is your number one priority. If you find a bike you like, but it isn't the right size, be willing to wait for them to order one for you.
Here's a shot in the dark; not a single speed, maybe not your thing, but I like it. Drivetrain is 1 x 7, which means only one shifter, but still plenty of gears for those windy days.

http://www.jamisbikes.com/usa/thebik...ter1st_sg.html