If you not opting for a Latitude I guess the top choice amongst most board members it the IBM T40. Pricey for specs, but everyone asserts it to have top notch build quality. I've heard some good things overall on the Toshiba Tecra S1 and M1, but there are reviews that say it's performance (M1) lags over other comparable lappys. I would never by a HP distributed anything. Haven't heard rave reviews on VAIOs.
IBM T40 appears to be your best bet.