Ditch the RX and SPI. RX is nothing special. The SPI sounds too stiff for your style of all-around riding. I personally love the SPI's, but I am also and aggressive rider. Even then, I would only use the SPI strictly for all-mountain freeriding and nothing else.
The best Ride binding for you in my opinion is the Delta. If you can afford, the 2011 Ride Delta's highbacks have been improved. I personally find them real comfy and the flex is smooth.
On the Rome front, from everything I've heard, the Targas are super steezy. You can adjust the hell out of them so it can pretty much cover every type of riding you do. Still a little stiff for park, but hey... you only hit it some of the time right?
Another Rome binding to consider is the 390 Boss. Not the stiffest binding, but cant bed options keep you comfy especially if you cowboy a duck stance.