Among the most commonly found today are the Intel Atom N450; the Intel T4300, Core 2 Duo, Core i3, Core i5 and quad-core Core i7; and the AMD Athlon 64 Mobile and Turion 64 X2.

Basically, the more cores in your processor, the more calculations it can handle at once, making for better response times when you're running multiple applications. Dual core is good for most purposes today. Processor speeds, meanwhile, typically range from 1.8GHz to 3GHz or more.

Of course, Linux can play well with just about any processor--even the lower-end Atom--particularly given that there are distributions designed just for low-resource contexts. For a nice, basic laptop setup, though, the Intel Core 2 Duo and the (slightly slower) dual-core AMD Turion 64 X2 could both be good choices for either a dual-boot or Linux-only scenario. If you're planning on performing tasks such as encoding video or running engineering applications, of course, the higher-end Core i3, i5 or even i7 might make more sense.

System Memory

RAM is particularly important if you plan to use memory-intensive apps like virtualization (via VMWare or VirtualBox, for example), photo editing (such as via Gimp) or video editing, or if you plan to dual-boot. Most laptops offer between 2GB and 4GB of RAM; many are also upgradable with more than that. If you go for a 64-bit Linux distro--or if you dual-boot--it's a good idea to go for 4GB of RAM for maximum flexibility. On the other hand, 32-bit distros alone don't typically need more than 3GB.