I loved the boss of the Ancient Cystern, ANCIENT AUTOMATION KOLOKTOS!!!
I swear, after beating him I still goofed around with his swords for at least a minute or two, feeling really sad about the fact that I couldn't bring one with me.
That entire fight was really ace though, beating the crap out of him with his own damn weapons must be one of the most satisfying experiences I've had during a boss fight in any game.
After that I was prepared to have a real hard time with the 2nd silent realm, because I've heard people on GAF say it was a lot trickier (?) than the first one ..but, I pretty much got it in one attempt. (two if you count my short lived experiment to see what the quicksand would do in the silent realm.. yeah.)
I'm in the Sandship now, which is.. dungeon 5? Though I didn't enter before spending almost all my money to upgrade my goddess shield to level 3, getting my last adventure pouch and doing something else that apparently wasn't important enough to remember.
I'm enjoying the game a lot right now though, I really like how the treasure hunting & side quests are a fun and easy stress relief to take your mind off of the intensity of some of the dungeons and bosses.