
The Dell (Latitude C810) I got for a case of beer. Heavy beast, well built, has a nice 1600x1200 15" screen that's better than the one in my new HP EliteBook.
The HP Compaq NC4010 cost me exactly 1€, including a nice suitcase with AC connection and a (supposedly working) Canon BJC-70:

The Dell got a RAM upgrade to 512MB (it's only recognizing 400MB - well enough) and a 80GB HDD I had laying around. It even started up Windows 7 from this drive! Slow as molasses, but it did work! Currently installing Windows 2000 on it.
The HP is a really nice, compact machine. Currently tinkering with Linux Mint Mate, after upgrading to 1 GB RAM. Surprisingly, the system is bottlenecked by the 1.7 GHz Pentium M instead of the RAM. It even ran well enough with only 512MB installed.
EDIT: I do have a spare 1.8 GHz Pentium M. Normally I wouldn't even think about disassembling a complete laptop for 100 MHz more clock speed, but considering the CPU is regularly at 100%, and with my old HP the increase from 1.4 GHz to 1.8 GHz was tremendous - it might even be worth it.