3d passthrough is what you need in order to pass 3d video content through an intermediary device. Basically, if you are outputting 3d from the Blu-Ray player, every device in the chain needs to know about 3d, or the content won't pass any further than that device. So if you are using a 2-year old receiver that is HDMI 1.2 or 1.3, then the audio + video will go from the Blu-Ray player to the receiver. The receiver will process the audio, but when it sees the video, it won't pass it through to the TV, due to the 3d flags in the content. So no video on the TV. The receivers that support 3d pass-through will understand that 3d video, and even though they don't process it, they will pass the video through to the next device in the chain, aka, the TV.
There are a couple of alternatives to getting a receiver that supports 3d passthrough. The first is to get a Blu-Ray player with dual outputs and have 1 output go to the receiver and the other to the TV. The other is to get an HDMI splitter that will send the same signal to both the TV & the receiver.
Note that this is only true for true 3d content. The output of a DirecTV box or other cable box is what is called frame-compatible-3d and doesn't have any 3d flags on it. The TV has to manually interpret the content as 3d and then display it in the alternating eye format.
W.R.T. 3d content, I think that it is amazing. Once you see sports in 3d, you will be hooked. Even though there isn't a whole lot, what is out there is pretty good quality. You can get the World Cup 3d Blu-Ray if you are into that thing. Either that or find a provider with ESPN 3D.