I don't think you should take fps in account when it comes to refresh rate. They're two separate issues.
Regardless of the refresh rate, there's no point in getting over 60 fps if you can guarantee that you never go below that number on the low end. Usually, a 60 fps average benchmark using a typical, in-game timedemo means it can crawl at 20 fps during heavy action or fly at 100 fps when you're standing still against a wall. The 60 fps "average" is exactly that, an average. The assumption is that the higher the average, the higher your "low-end" fps will be.
A higher or lower refresh rate should not effect your fps, but it does effect eye strain. The higher the rate, the easier it is on your eyes. Stare at a monitor to with a really low refresh rate for an hour and you'll know what I mean.