If you like DQ VIII, get Ni No Kuni for PS3, it's a spirtual successor to it and it's GREAT. Think I put about 60 hours into it, and I still haven't done everything.
Final Fantasy Tactics for PS1 is AWESOME, one of the few games you can actually lose and have to restart your whole game if you aren't leveled up enough.
Any of the Operation Rainfall game for Wii are great. Xenoblade, Last Story and Pandora's tower. Xenoblade is one of the longest games I've ever played haha, I'm at about 50 hours, and I think I'm MAYBE half-way?
Skyrim is always a good choice, especially on PC
Rogue Galaxy on PS2 was a great little overlooked RPG, tons of fun and a great setting.
Skies of Arcadia for Dreamcast/Gamecube is one of my all time favorites, the normal combat is pretty good, but you have these awesome ship battles that are one of the most fun battle systems EVER. Pick it up for the Gamecube if you can, comes with some extra quests and stuff.