I really can't add much more to what Jimmy4 said either, I have the same T40 as well. It is bad ass. It's got everything I need and the combo of touchpad/joystick is key.
2 additional recommendations too -- get the IBM Battery Option (larger battery) and an extra power supply. The better battery with the T40 is exceptionally nice but I would recommend these accessories for any laptop really. These 2 parts always seem like the first to go or get damaged or lost etc., and it's cheaper if you buy an extra power supply and battery outright too, rather than waiting till you eventually need it. Oh yeah, get enough ram too, at least 512, 768MB or 1GB (go for the gig if you can!!!! It's worth it on any system.)
The large battery on the T40 is seriously killer. Between that and a fully-charged normal one, when I'm on the road it seems like I can go all day! I just spent a week in NYC and only had to plug in each night to recharge.
Only complaints about the IBM T40 is that it doesn't have an onboard floppy drive or 9-pin serial port (both of which I need for work) and the wireless card won't work with my protocol analyzer, but you're good to go if you don't need any of that crap
Also, I really like Toshiba laptops because they are rock-solid. I just retired my Portege' 1040CT and it was a great workhorse for 3 years, but even when comparing my impression of each when they were new, the IBM T40 leaves it in the dust.