I would recommend staying away from the older stream pumps (with the pucks).. I've got a 60" 90 gallon tank and I can tell you that a nanowavebox and two 6055s do a GREAT job of making sure that everything, everywhere is getting the flow/current that it needs to thrive..
bottom line is that tunze makes powerheads that are static (always putting out the same flow) and powerheads that are controllable (variable flow that can be changed without using a controller)
static powerheads look just like the controllable powerheads so pay attention to the GPH flow listed next to each powerhead. if it gives a range (750gph-1500gph) then that powerhead is a variable speed/controllable powerhead.
controllable/variable speed powerheads can be controlled using a tunze multicontroller (for creating waves/alternating flow/etc) or they can be controlled using aquarium controllers like the APEX.. (does the same thing as the tunze controllers)
that's the readers digest of it.. if you have specific questions, post them here or pm me and I'll see if I can answer..