As is, Lion is worth exactly what they're charging for it - $30. Now, if they had left Spaces alone, or at least given us the option to turn off the turkey known as Mission Control, I'd easily be willing to pay upwards of $75 or higher, *just to keep that feature.*
I'll bet Launchpad will be wonderful for a novice user who enjoys using their iPad. Well I have an iPad too, but I won't be using LP. What's the point? I don't have a laptop (iPad *is* my laptop), and if I really need to see all my apps, that's why my Applications folder is down in the Dock.
Just another thing Apple did to make things nice and simple for the casual users, while taking away things that power users care about.
I do like full screen apps in some cases - not every app needs to be fullscreen, which is how I used to have apps in Windows, and I'd just have to alt-tab through the list to bring the app I wanted up front.
If someone decides to write a Spaces replacement as a third party app, I'll buy it 🙂
Overall, not bad for what you get, but as someone said earlier, Apple really is becoming more and more a mobile devices company, and seems like in 10 years, they may only offer laptops...