I just got an hp Pavilion DV4000 for the things my Tibook can't do:
Inventor 10
EasyC
VAG-COM (for talking to my car's computer)
I'm still setting it up, so I can't give you a real evaluation, but so far it meets my needs. I decided on the hp mainly because it was the least expensive laptop which offered a graphics card compatible with Inventor (ATI Mobility Radeon X700, 128 MB), though it's probably the lowest spec machine which can run Inventor 10 properly.
If you plan to run Inventor, I recommend you check their
graphics card certification page before you buy.
Some other specs:
Pentium M 740 (1.73 GHz)
1 GB RAM
60 GB HD
DVD/CD burner
XP Pro
$1425
It has all the usual connectivity and a decent package - about the same size and weight as an Inspiron 6000, but cleaner styling, fit and finish. Still not as nice as the Tibook, but that's to be expected!