The London Eye should not be at the top of your London to-do list.
That advice comes from someone who loves scenery and aerial views. I'm always the first to say "let's go to the top and take lots of pictures."
But a "flight" requires spending substantial money (the lowest single ticket price amounts to about $1 per minute of viewing as of this writing, and London Eye ticket prices rise from there. They also go up after May 31) and operates in a city where cloud cover and fog can be a fairly common condition.
The picture above is clear evidence that I did not follow this advice. But my visit during the late winter involved clear skies and very short lines. In summer, when tourist season is in high gear, you will invest precious time as well as money for a chance to snap pictures of London from above.
If you're an avid photographer, budget for a visit here. But many others (especially those with families in tow) would do better to direct their resources in a number of other directions.