2-channel vs 3-channel/5channel

I have been enjoying some B&W N802s for movie watching in 2 channel. A real pleasure. My question is, will I gain a lot of enjoyment by going through the complication/pain of setting up 3.1/5.1 or is 2 channel "enough" for movies.
I've been there and done that. For me it was a waste of time and money.
With excellent imagining speakers I don't miss a think when I do watch a movie.
To be honest though, with my good 2- channel system I find myself wanting to enjoy good music rather then watch a movie.
So anyway, to answer your question, a good surround sound system not only gets you tremendous added dimension on movies, but SACD and DVD-A's cab be astounding.

As long as you don't mind effects that should be coming from the back or sides not coming, then your 2 channel system should be fine. If you want the immersive effect, then go for the full system.

This is the wrong forum to ask the question on anyway, as most would probably want to go back to mono given a choice.
I have found 4.1 (no center) to be MUCH more enjoyable than 2.0 for movies. I have sold off my surround sound a few times and always regret it.
Let yourself make the decision: Watch a action movie in surround sound at a theater, do you feel that you have the same enjoyment at home with your 2 channel?
If you do decide to move to surround sound, I'd suggest adding the center channel last as you may find you don't need it (so long as your processor can direct center channel dialog to the mains).
I have had a Meridian analog or digital system system as well as my 2 channel analog for a long time. Analog is great in 2 channel and they did try 3 channel as well as DD surround but they never really worked well IMHO. Meridian did an analog Trifield and still does in the digital domain that is very good and can sound better than 2 channel if done correctly. A system setup correctly will sound best but with trifield you do not have to setup speakers perfectly as you have control of things like depth and delay. So if your setup area is difficult the system can compensate for some but not all your problems to make it at least listenable. I listen to most of my music video's in trifield. I find they hold together much better than in 2 channel or a surround sound setting. I find most music video's recorded in DVDA or SACD Surround put me in with the band, not in the seats where I would be if I purchased tickets. BRay and DVD video's do a better job but some of that I think has to do with the video as it is not all up to our ears and minds to put the instruments into there locations on stage.

As much as I love my 2 channel for music, Right now I'm unable to set up the surround system for movies, and I miss it like crazy. 2 channel just doesn't cut it, esp for things like Apollo 13 etc.
I will be trying it out in the future. I have all the necessary ingredients. Arcam AVR600 / 805N for the back channels. I just don't have the center - which I might not need.
To answer your question, yes, you will get a lot from the addition of one or several channels. Adding channels gives the potential for improved sound, but...that all depends on execution.
If you get good imaging in stereo, you may not need a center channel for HT. We use the same 6.2 setup for music and HT, although I rarely turn on the amps for the two rear channels, so we really use a 4.2 setup, and it tracks dialog very well. I removed the center channel, because it didn't seem to contribute to the sonic experience.