The largest show in Ohio, West Shore Orchid Society Show, is almost here. Like Windswept in Time Orchids and Roberts Flower Supply, it is a few hours travel (I live south of Akron) so I usually buy most of my orchids online.
The American Orchid Society
There are many great vendors that have good websites and sell online.
What type of orchids interest you?
Hausermann's Orchids is where I do most of my online orchid shopping. They have nice Phals, Cattleyas, and a variety of other orchids, including species. Some are young orchids a few years from blooming while others are blooming size (they usually indicate this). They are in Chicago and have been in business a long time.
I buy small Cattleyas (and a nice Encyclia) from Sunset Valley Orchids. They also have Catasetum. These are usually not clones so the results can be hit or miss. I have some nice orchids from there.
Ecuagenera and Andy's orchids both have a wide variety of orchids that many other vendors do not have. I have bought from both in the past and gotten healthy orchids.
If you do not mind a hundred dollar minimum, Exotic Orchids of Maui ships healthy but usually very young orchids. I have bought from them in the past.
Some of the other vendors I have used have closed.