Well seeing as I tend to veer away from crappy games (in my opinion), I don't have many that can go into "worst".
Best would be:
The Witcher 2 - Best fucking RPG I've played in years and had me hooked from beginning to end. There was nothing I really disliked about this game save for a few technical issues that were cleared up in later updates. I eagerly look forward to the 3rd game and see how things will unfold. It's Choices and Consequences put every other current day RPG that flaunts that attribute to shame. Overall and excellent RPG and I look forward to patch 2.0 at the end of the month which adds Dark mode (with dark gear), and arena mode. Will make for a fun and challenging 3rd playthrough.
Deus Ex: Human Revolution - Another really good RPG with great story and gameplay. It had great pacing, fun gameplay, and hell I liked the boss fights. I don't mind that the game looked a little dated, the art direction was still excellent. It was like if they brought the original Deus Ex into the modern generation and fixed all the tedious aspects of it.
Tactics Ogre: Let us Cling Together - Just like the other two entries, excellent story, deep and satisfying gameplay. I love SRPGs, I love political drama, and I loved FF Tactics; and this is what you get when you put all three together. I've always loved Tactics Ogre and this enhanced remake was just great.
Worst? Well....
The Third Birthday - Seriously....WHAT THE FUCK!? They resurrected Parasite Eve only to shoot it right in the fucking face. Thank Motomu Toriyama, you've added another abomination to your resume to give all the more reason you should not be allowed to write.
I'd also put Duke Nukem here as well, but I didn't play it. I knew it was going to be shit anyways, and I wasn't surprised one bit at the critical reception is garnered.