We found that Legoland lived up to the expectations set by our 4 year old's exposure though various sneaky means to the mega-branding machine that is Lego corp. There was a good balance of moderately thrilling rollercoaster rides (dragon-style coaster emergiing from Lego Castle(tm), with more sedate physical experiences (Lego helicopters(tm) rising and falling at the throw of a level at a snails pace).
I found the park more pleasant and enjoyable than expected - it's nicely laid out, with trees & winding walkways, not too too big, not overly crowded & relatively calm. We were there on a weekday though so I'm not sure how busy it gets on the weekend.
Tip for the beginning: don't bother with VIP parking, regular parking (which you still pay for) is only 5 minutes further to walk to the entrance.
Tip for the end: avoid the shop just before closing time - it was a panic-inducing frenzy! See more at bigbluetrunk: http://bit.ly/gCMGYV
The 128-acre complex was built using more than 130 million Lego blocks, and features 50 rides and eight themed areas. In reality, the park activities will interest kids 2-12 years, but visitors of all ages will enjoy the fantastic Lego constructions that adorn the park and the detailed artistry of their builders. See more at Family Travel Forum: http://bit.ly/aPLWij