Hmmm...I figure I'm probably best equipped to chime in. Last July, I bought a Ferrari 4005. I sold it in November for a T43. In July of this year, I'll likely buy the new Ferrari, but certainly not to replace my T43.
The Thinkpad is better. As much as I love the Ferrari, the Thinkpad is just a better laptop. Sure, I prefer the rubberized coating on the Ferrari, but the TP is thinner, lighter, cooler (temp), has a better keyboard, a trackpoint and thinklight, and has better battery life. More options. 2nd HDD? no problem. I have 2 80gb 7200rpm drives in it right now. Extended battery life? 9 cell + ultrabay battery = 9 hours of battery life. The 4005 routinely got 3 and a half for me...but there was no provision for extendd battery life.
But let's be honest. We're comparing what was the best gaming laptop in the 15.4" form factor against the best thin & light laptop that was available. Well, the 14" at least. I liked the 15" T42P that I had, but the 14" was always the sweet spot for me. Portable but powerful, and under 5lbs.
Different classes. Different intentions.