There are a lot of options.  Hyatt Regency and Hilton Columbus are all near the convention center.  Sheraton at Capitol Square is near the state house.

The pickings are pretty slim in Columbus.  If you want some recommendations, let me know

Hilton/Polaris sure is nice.

Thanks all, I appreciate the reccys greatly.

parking, some ya can park yourself either way it's an extra expense for the ladies or they're going to look suspect parking a block away with all the extra patrols they have driving up & down the streets to see her walking with her bags to the hotel (gives them a chance to run her plates)....
Hand's down the Crown Plaza is the best & really knows how to make your stay worthwhile with memmories...also if your wanting discretion
The Hyatt & Drury Inn-with the convention center right there, she can park herself, it's private & leads ya right into the hotel with an open lobby always full of people.  
The Reinnasance is also super nice with hidden parking that she also can park herself....they all charge a parking fee but it's inexpensive & worth it, some like the Crown Plaze will include valet with your room.
The Courtyard has parking on the street- but it's right in front, convenient & no extra fee.
Have fu