For me most of the games I've always wanted to play I haven't because of time limitations the last few years. For example.
Panzer Dragoon Saga - got a Japanese copy just waiting to be played.
Phantasy Star 1-4 - picked up the phantasy star collection recently on psn to help finally play this.
Lunar 2 Eternal Blue Complete - again, lack of time has prevented me from playing this. I need to play it soon.
Snatcher - got a playstation copy of this. Wish though there was a psn version so I could play it on my vita, but sadly there is not. I wonder why.
El Dorados Gate - got almost the entire series last year in akihabara (somehow forgot to pick up the last game). On my to complete list
The two capcom dungeons and dragons arcade games - always held back on buying the Saturn versions because of price. Will finally get a chance to play in August when it's released on ps3 in Japan.
The Legend of Zelda A Link to the Past - sadly for some reason I've never owned this game. Will probably buy on the virtual console this year finally. Just wish there was a 3ds version I could play.
Mother 1,2,3 - just bought the whole set on gba. Hope to get through those after finishing shin megami tensei Iv right now.
Far East of Eden series - got a PSP collection of this a while back due to a friends recommendation. Looks fun for me.
And those are just the main ones. There are a ton of games in my collection I've gotten over the years I want to play more of but haven't. All I know is, I got plenty to keep me busy in my free time for many years to come!