Linux can be optimized, fellas.
The issue is, how much are you willing to screw up, and how much do you want to learn?
Some relatively easy fixes:
First, you can shut off unneeded services, such as Samba, and Apache, on a laptop. Also you might want to consider shutting off any networking by default, since we're talking laptops: it might not be always connected. You can restart it later via the console.
Second, you can recompile the kernel, removing support for anything you don't need. The kernel is getting big, and can run everything from a lappy 486 to a mainframe. You don't need everything loaded. Follow the directions to the letter though, or your system will get fubared.
Third, you can aggressively manage your memory. IF you are running KDE, and you have only 256MB, you've got a problem. Linux is, at it's heart, Unix like, which means real multitasking, which places a premium on RAM.
You can get around having low available ram by forcing the kernel to drop everything into the /swap partition, but since I've never done it, I don't know what sort of increase you can get from it. More RAM is generally better, and cheaper, so, get 512 or greater.
If you can't get more RAM, consider using another DE as a host for KDE apps. For example, XFCE is pleasant to look at, functional, but takes up less system resources than KDE. If you open KOffice, for example, while in XFCE, it's only going to use the processes it absolutely needs to support the app.
Finally, you can play around with the CFLAGS when you compile/recompile. A good link on this is:
http://linuxreviews.org/howtos/compiling/Gentoo users are old hats at this. Consider this the advanced option. There is a link off that page which gives safe CFLAGS options by architecture.
Good luck.