Don't forget to get one without a glossy screen. It will limit your choices, but you can't work with a glossy screen. Trust me. These days the only models where they offer the option to get non-glossy will be business models. They are slightly more expensive, but also usually more durable.
Second, you should stop the dual-booting and start virtualization. VirtualBox or VMWare or whatever. I don't use VMWare, because they didn't have a deb package last time I tried and the rpm installation was pretty ugly.
For virtualization the best idea is to get virtualization support in the processor. AMD-VT or Intel-V. The cheaper Intel models dont have it. Which I think is very disapointing. I don't know why Intel does this and I don't like it at all. Because virtualization gets more and more important. Maybe they think they can sell new processors later, when people will need that feature. Because these days most people don't need new computers any more. Whatever it is: I usually would opt for AMD, but that REALLY litmits your choices, because business machines with AMD are hard to find. The only model for a good price I could find was the HP Compaq 615. It comes with glossy and non-glossy screens.
I also like the Latitude 2100 netbook:
No drive bay at all, no CD. If you need stuff, get them USB. Much cheaper than proprietary drive bay drives and features.
Obviously you will need to use VirtualBox (or whatever you prefer) to use other operating systems. And the Atom processor is not very fast. So maybe you won't take that one after all.
But netbooks are very nice, because they run very long and are very portable. The Latitude 2100 is the only netbook that comes with non-glossy screen.