I loved my T41p. It was so pleasant to use that it became my main workstation. Unfortunately, the battery stopped holding a decent charge and the fan stopped completely. Since Macs were growing in popularity, I needed one for testing, so I made the switch to a 17" MBP. It was rough at first (I really miss the pointing stick, extra trackpad buttons, and the incredible range of the hinge on the T41p), but after three years, I'm still impressed by the design and quality of the MBP. Most other laptops seem old and clunky by comparison. As for Linux development, VMWare or VirtualBox allow you to run multiple distributions and you can back up images for easy restoration. As for common open source tools on the Mac itself, MacPorts has the essentials and more.