If you want to make adventure games like the one in MI or CMI or Even sierra games, try using either Wintermute Engine, Agast, RoBot (Which I dont think is being developed anymore), Mad(madproject.sourceforge.net), or my personal favorite: AGS (
www.agsforums.com)
It is awesome program with an editor in Windows. You can make games for all windows versions, Dos, and Linux. You can also add langauge translations to it and make plugins in C++, as well as many other scripting things like Structures, making your own events and functions and more... People dont think its very powerfull becouse you are allowed to make games easily, but thats not true, it is really powerful. It even has a great community. It can make all types of guis easily like MI, Zak McKracken, Indy, CMI, Full Throttle, Sam N Max, All sierra agi and SCI games (Supports text parser, multiple GUI's, Conversations, different character views, multiple characters control etc...) Many great games have been created with it, and it is updated almost every month.
You could also try SCI or AGI Studio, that could make some good adventure games. And if you are patient, Brian from SCI Studio has said that when he is done with SCI Studio and some other projects, he is going to make a SCUMM STudio.
Joey