I think Escape the Museum is one of the best solving puzzles/hidden objects games. You can take as long as you want to find the objects, but beware of clicking on the wrong items. Your score goes down very quickly.

I am about 1/2 way through the game and I love it. It has the hide and seek features, some are quite hard but you must also collect clues and escape from each room. You get rated on time and percentage of correct finds. Your score drops significantly when you click on the wrong object or use hints the first time and a little less every time after. So time is not as much of an issue as in most games of this type. Story is a wee bit corny but aren't they all. It is probably one of the bet HIDE/SEEK games I have played due to having to escape each room. Highly recommended. If you like this type of game, I recommended

http://www.azureusgame.com/Puzzles/Escape-the-Museum.html. Hope to see you there!