Aquaboy: go for the 10'6" length. It seems everyone is pretty unanimous in that opinion. Couple of other advantages:
better control of your line/float when you're drifting a float. Better hook sets because of the mechanical advantage you get of a longer rod. Generally, longer length=more/better shock absorbtion when the fish runs on you thererfore, is "more forgiving". You can still cast well with a 10'6" rod, but it's a lot harder to drift a float with a 6'6" rod especially if you're fishing in a crowd and everyone else is using a 10' + rod. FYI: for targeting pinks I wouldn't even bother pulling out my drift rod. I've got a Daiwa Eliminator (7') with a Quantam Energy reel which I've used to land 8lbs pinks and 6lb cohos when casting spoons. I've also got a 9' Triforce Z rod and Abu Cardinal reel if I want something a little more substantial for pinks. For springs, the 10'6" rod is the way to go.