What niche PS2 games are worth picking up?

[Doobie_wop]

So with the help of everyone in this thread I've decided to pick up God Hand, Silent Hill 3 and Persona 3 tomorrow. I'm also gonna keep an eye out for Ar Tonelico 2, Kingdom Hearts 1 and I'll probably pick up Odin Sphere at some point.

Shadow of the Colossos and Ico will have to wait for now and hopefully Sony have the sense to release a HD collection. 

I'm going to pick up more PS2 games over the year and then kick start my Gamecube collection again or just set up an emulator or something. I'll also continue my long and dangerous search for a copy of Yu-Gi-Oh! Duelist of the Roses, I hate the anime, but I had a two hour encounter with the game back in 2004 and it hasn't left my mind since then.

Thanks for the help. 

P.S. God_of_War_Forever you were wrong, Orphans pretty awesome. Just sayin.