The London Eye has established itself as one of the must visit attractions of London alongside such favourites was the Tower of London and buckingham palace. In fact it's the most popular pay for entry visitor attraction in the UK. It's rather pricey at £15.50 per adult and £7.75 for kids under 16 years of age but you save 10% if you book online.
The London Eye, at 135 metres, is the tallest observation wheel in the world. I think that the London Eye is most spectacular to non-riders when it's illuminated in the evening.
I took a "flight" on the London Eye in 2000 during its first year of operation when I visited the Millennium Dome with our sons. I was rather wary as I generally feel sick during any sort of fairground rides. However the London Eye's motion is smooth and slow and I was able to enjoy the views without feeling queasy.