Dragonlance is a blast if you have a creative DM. It is limited if you stick to the rules
but a LOT of fun. Greyhawk is from the old old school with modules like Keep on the Borderlands and that Giant serie, thr name escapes me at the moment. Granted most and written mod can be put into any setting or game world, and eventually you will find yourself making your own. It all comes down to a couple basic thing's, who the DM is and what caliber of players you have, you could have the worlds gratest DM or be that one and have poor players and never have any fun or vise versa. Play around and enjoy, stick to 2nd ed or 1st ed, 3rd I find to be a bit off the mark, there are some great idea's and what have you but.... Enjoy