It's only my opinion based on the puzzles that I have played with. I cannot comment on the puzzles I have never played with and hence I may miss nice puzzles in the list.
The order of the puzzles does not mean that the first one is the best.
1. Angel box by Wil Strijbos
One of the best example of the sequencial discovery puzzle.
Many steps, many tools to free the angel. A challenging puzzle!
But take care not to loose tools (yes you can...)
2. Pachinko box by Wil Strijbos
In my mind the second best Strijbos puzzle. Many steps, and unexpected ones as well. You have to get the 2 coins to solve completely the puzzle.
3. Lotus by Wil Strijbos
A deep blue puzzle that has several steps. The first one was blocking me for some time then came the aha moment.
The puzzle is solved when you understand the name of it... ;)
Tools can be lost. Tools can fly out. Take care!
4. First box by Strijbos
A pretty heavy box that has its secrets. Make the puzzle smile!
5. Big Ben by Brian Young
A pretty huge puzzle with a lot of challenging steps
6. Houdini torture cell by Brian Young
Not difficult but satisfaying puzzle. The picture on the right is when the puzzle is solved...yes it's tedious....
7. Butterfly by Wil Strijbos
Big puzzle, but this time you will have to deal with a massive lock. Analyze the puzzle carefully or you will jam your puzzle and beg for help (and external tools) ;)
8. Packman by Gary Foshee
Despite its very small size, many steps are required for this challenging little cute puzzle!
9. Gary's escape by Gary Foshee
Easy one, but clever steps.
Free the marble!
10. Open lock by Gary Foshee
Nice lock. Seeing the inside does not mean you will find right now the solution :)