Cycling shoes are flat by nature and I have really high arches, so I put an extra pair of arch supports/orthotics in mine and that works great! My shoes are Shimano and I've had them for at least 6 years. Unlike my running shoes, they never wear down!
I have two pairs that I really love. One pair of Serfas Astro- love the snap and tighten buckle feature on these. The other pair is Sidi- these run a bit smaller and more narrow than the serfas and have three velcro closures. Both are very comfortable and supportive.
The Serfas I purchased from StudioCycles.com. The great thing about buying from there is that they send the shoes with SPD cleats already installed and adjusted. If this is your first pair of cycling shoes you will want to ensure that you also order the cleats if they don't come with the shoes.
I, too, have Shimano. Got them on Zappos. Love them. I think they were $80 or 90. Not the absolutely cheapest pair, but moderate - not even close to the most expensive. Worth every penny.