I don't really have any "grail" games, but the English DOS release of Zeliard is a game I've wanted to own again for years. Even diskette-only copies were quite expensive. It's an early Game Arts title, and like a lot of Japanese PC games of the time, rough around the edges but full of charm.

I found out it was also included in the Sierra Action Five pack, which I was also looking at. In the end though, I got this really nice copy of the game for a fraction of what most people are trying to charge for it. Now back to buying more hoyle games LOL