I absolutely echo Marissa C. in terms of my feelings about Las Vegas Boulevard. I absolutely hate the strip, and avoid it unless I have to (usually to check out a restaurant or to go shopping).
That being said, the Bellagio's conservatory is one of the few things that truly shine as being enjoyable for all ages, breathtaking - and it's FREE! I always bring my Vegas visitors here because it doesn't take long to view, and it shows a different side of Vegas.
The floral arrangements never cease to impress, and there is always such a level of detail that goes into each one. It seems to always have something to please the kids, while also has something that gives adults a reason to visit as well.
Most recently I went with friends Izzy and Val (with her 3 year old son Xander) to see the Holiday 2011 view. Everything is stunning, and there were floral polar bears and penguins, as well as a train that had a little camera in it. Xander, who is in love with trains, was dying of excitement when he saw the trains.
I recommend going in the daytime (morning) if possible..it crowds up VERY quickly.