Well, got the slot fan (Antec Cyclone). It brought the system temp down to 48-50, so not a big drop. Helping the graphic card temp by a degree or two at idle as well. Didn't bring the system temp down as much as I thought it might. At idle the air blowing out from the slot fan is barely lukewarm, and after playing a game or something intensive, is pretty warm, so I know it's sucking hot air out.
Maybe there is just an inaccuracy with Fanspeed, or I'm just not getting air directly to the sensor. Interestingly, after installing the slot fan, CPU and core temps (all above the graphics card) also dropped a few degrees. CPU is idling around 27 now.
Might continue to play with fan placement, but since I'm not crazy about this case anyway, might still upgrade it at some point along the way.