Most people I give PC buying advice to really don't think like I do -- either they want a $400 computer, or they want some $2500 thing with some gimmick feature set (custom color lid? who cares? lightscribe blu-ray burner? do that at home! Vista turbo-memory? Why?). For this reason I sometimes over-discount my own opinions about them when I'm advising others.
I personally agree about Thinkpads not being ugly (when I made that comment I was referring to my wife's perception of them initially -- now she's a T61p WUXGA convert as well).
I also agree about Thinkpad reliability, but I know the plural of anecdote isn't data, and everyone's mileage varies.
I disagree about the T series weight. The T grew to fill the void left by the discontinued ~7 pound A series. Yes it's lighter but I feel sorry for any floor it might land on... but the computer will most likely survive.
I fancy myself a power / heavy professional user as well: I have a very low tolerance for hardware related BS. I run minimalist installs of the OS of my choice (XP at the moment). I expect to be able to throw my computer around (while off -- I'm not a sadist) and not scuff or break anything. I disable or order machines without gimmick features (Bluetooth is disabled on my T60p, I got one without the fingerprint reader), and I don't use the full (software-integrated) versions of drivers for anything I don't have to.
With this recipe, my Thinkpads have been very faithful to me over the last ~10 years, and Lenovo's going to have to really screw it up to lose me as a customer.
Depending on what you're looking for I'd say that IBM/Lenovo is ahead of even Apple on build quality. In my opinion Apple pushes too hard on fine design (fine lines and edges, thin case designs) where the Thinkpad team designs their machines to take abuse first and foremost.
If you're the type of person who values these properties I believe a Thinkpad should be on your short list.