Myst for iphone render very well on the ipad except for the texts but they are easy enough to read. Just a great game but difficult puzzles.
I'm playing now Laura Jones and the Gates of Good and Evil. It's tagged as a find item game but there's more and there's a real feeling of adventure and find item games are much more than I believed. Dreams HD currently free is probably in a similar category.
Stranded 2 Mystery of Time : If this iphone game has graphics a bit blocky on the ipad it's good enough to enjoy this special game. It's a merge of Hack&Slash with adventure and a mood of RPG because of the wandering freedom.
EDIT: Ho my god, totally out of topic, I can't delete, if a moderator could delete this post for me...