It all depends on what you want.
Soundbars -
They offer decent sound quality and they are aesthetically pleasing and easy to hide. They're also far cheaper than a surround sound system.
If you aren't trying to replicate a movie theater than sure this is the best system for you. Would I have got the same experience using a soundbar vs the experience I got using a decent surround sound system? Absolutely not. My friends in college all had soundbars, I had the only surround sound setup. Even with my subs off, you could clearly hear music/tv from my room because I had that headroom. Soundbar, there is no way it could really immerse you but that's something you obviously know going in to the situation.
A sound bar may be all you need. But to say it comes remotely close to a decent surround sound setup is highly amusing. There is no way a soundbar can come remotely close to a decent surround sound setup in terms of volume. I'm happy with my setup for what I paid for it, I'd want more if I could get it, but I'd only use a soundbar if I was listening at moderate to low volume levels. If I want to be fully immersed ina movie, surround sound is the way to go.
Edit: As for the above comment Hexen said about listening to music in their living room. Many times I simply just turn music on then go about and do stuff in the house. Having my system on fills the whole place with music and that system is in the basement. In the living room, if I turn on music it does fill the whole house and give a very nice ambience. But I do actually sit in front of my system sometimes and listen to music while eating or something or even just sit and listen for a bit. It's really nice to actually just focus on the music.