I need some help/advice. I recently converted my 10 speed into a single speed and I love it but i'm anxious to convert it to a fix. I'm riding a 42/17 right now. I basically just stuck with the gear that I rode the most before I stripped all of the crap off my bike and it's pretty comfortable for me since Chicago is very flat. But I was wondering if anyone who rides flat terrain a lot could give me some advice for a gear ratio that might fit me better. I'm anxious to get a new set up, but I don't know how to decide what ratio to run without spending a lot of money to find out.

Please help with any advice or knowledge. Thanks I appreciate it.