I'm not good at top 10's... but Chrono Trigger is one of my favorite RPGs of all time. Remember all those endings and New Game+? Even after it ends they give you reasons to replay it... genius! And you really can't go wrong with Toriyama-san's characters.
Plus frog song is probably the most triumphant video game song of all time!
Also loved FFIV and VI (II and III in the U.S.). It was all about Sabin's blitzes. And of course FFVII! Epic! What happened to the FF series afterwards?! IX was all right, but I am sick of the rest -- "interactive movie" deals that don't deserve to be called RPGs.
I'll throw in my vote for the Resident Evil series (excluding the horrible REIII) in the action/adventure categories.