Marybeth, you need the fins to be comfortable. When I did my Open Water course, the fins were part of the rental package, and as I did my course in a warm water place, they were the full-foot type. Well, I have high arches and the rubber foot pocket constantly cut off the circulation to my toes. I spent every dive with cramps in my feet, so my very first gear purchase was a pair of open heel fins and tropical weight booties. Getting open heel fins and booties cost a whole lot more than getting full foot fins would have cost, but it was worth the expense to me.
Another thing to consider in terms of comfort is the blade style. There is almost religious debate here on SB regarding split or solid blade fins, but don't let yourself be swayed by any arguments other than what is best for you. I always recommend split fins for students who have knee or ankle problems since they put less strain on the joints whereas heavy rubber fins are very stiff and require strong legs. I recently had one excellent student who had had ACL surgery and who therefore dives with split fins. She could do everything with those splits that people say one cannot. But split fins are significantly more expensive, so if only for that reason, I would say to get full blade fins unless you've got joint issues.
The last thing to think about is how heavy the fins are. Solid rubber full-blade fins tend to be quite heavy, making them useful for diving with a drysuit and undergarments, which tend to make it easy for your feet and legs to float up. These fins will help keep your feet down. On the other hand, if you plan to do dive travel to warmer areas, their weight works against you for baggage weight issues. I travel with lightweight fins, but weight restrictions here in Asia are very tight, so every little bit matters a whole lot!
All in all, I think the Avanti Quattro by Mares is a great option. Nothing fancy, sort of mid-range in terms of weight, stiffness, etc. They work well for both tropical and cold-water diving, are rugged (I've had my current pair for about 6 years and I do a LOT of diving), neither cheap nor expensive....