Grandia 3. I loved, LOVED the first two (and Extreme was okay, I guess)... but I've never even seen a copy, so I've given up looking for it. Too bad, too, because it looked SWEET. Also, Halo. I really, really tried with Halo 3. Just not my cup of tea, I guess.
I'm a huge fan of the Gamecube, but for some reason, no matter how hard I try, I just can't get into Metroid Prime. I've owned it for years, but I've never beaten it. Same goes for Pikmin 1 and 2, actually... but I'm currently trying to force myself to beat Pikmin 1.
Pikmin 2 is miles better (imo) than the first. The first annoyed me quite a bit but they fixed a lot of the faults the 1st had in the 2nd.
Hmmm, your post inspires me to try Pikmin 2. I loved number one, but I gotta admit, I was pretty young when I got it near its release, and that game was pretty damn tough! I have yet to beat it either, I got close the last day, but I needed way more parts, so I just quit playing.
Just can't get around to beating pokemon red,green,blue, or yellow yet there my favorite pokemon games