I've had a T60 for about 16 months now. What exactly do you like about the keyboard? I've found that the keys have a tendency for things to get stuck in their movement, and the ] key had even fallen off of my keyboard. Then the whole keyboard stopped working, so they sent me a new one. I've also gotten a new power adapter (insufficient strain relief).

I personally like going with the three year warranty (but in a bundle rather than explicitly adding it on). I previously had a T22 that I ran into the ground, and over the course of its life had the motherboard, drive, and power cord replaced.