I use rods from 4.5 foot to 7.5 foot, depending on the situation. I also use three poles without rods from time to time, one 12 foot, one 16 foot, and one 20 foot, also depending on the situation. If you are using very light lures, 1/64, 1/80, or 1/100 ounce, a longer rod will generally give you longer casting abilities if you are not using bobbers. Just don't get too stiff of a rod once you start getting into crappies because they are extremely easy to rip a hook through their lip. Where you can set the hook with a bluegill/sunfish, I have found it better to just easy the rod tip up or back on a crappie. Either way, it sounds like you are on the right track with a lot of great advice. That's exactly why I have loved being a member of this sight for the past 7 years. Most people are more than willing to offer whatever help they can, and will rarely offer anything but constructive criticism.
It is not about the equipment you have to use,
It is about how you use the equipment you have. :D