In an earlier post I wrote that my first impression of iMovie '08 was very positive, and now I'll add that my longer-term impression is also very favorable. I've created several short vacation-oriented movies so far, and I've been able to add movie clips, pictures, voiceovers, and sound effects without ever having to read a manual (which is really great, since I had never created a movie before).
For instance, a few nights ago I kicked out an eight-minute movie of my five-month Alaska vacation. I added dozens of pictures and a few videos, then added transitions, voiceovers, and background music. I found everything to be intuitive (with the possible exception of ducking the background music, which I still figured out pretty easily just by poking around).
I think it says a lot for the application that the hardest part of the whole process was trying to decide which content to include or exclude. If the application was well-designed for adding content, I think it was also very well designed for editing content, which is more important on larger projects.
So, after creating several real videos and sharing them with friends, I still give iMovie '08 a thumbs-up.