As long as you choose a resolution with the same aspect ratio as your monitor, you shouldn't get black bars on the edges of the screen (even with a different aspect ratio, I think the default in your video drivers would be to stretch rather than add bars).
For the refresh rate, in an earlier version someone had resolutions listed in the game at 59 and 60Hz (desktop at 60Hz); using a 59Hz resolution in-game caused a crash when using spells, whereas the same resolution at 60Hz was fine.
