So, last Friday I finally got around to upgrade from Debian Lenny (Stable) to Squeeze (Testing), but not without facing some problems: network-manager got restarted too early while I still needed to download more packages to finish the upgrade, I got stuck for 20 minutes trying to convince cnetworkmanager to make the wifi adapter work again until I figured out I just needed to restart D-Bus, the Linux kernel package v2.6.30-2 in Squeeze has some patches that rendered the wifi adapter completely useless after restarting, had to quickly rebuild a custom kernel to solve that, and work with Squeeze's udevd and get rid of the annoying default console bell (BEEP! — in a university library, thrice), and then had to build another kernel enabling PAT support because the new X.org needs it for some reason or radeonhd gets unusably slow — phew.
It was much better than I expected and the migration from KDE 3.5.9/10 to 4.3.1 was relatively seamless; Opera 10.0 and VirtualBox 3.0.10 for Debian lenny still work fine after the upgrade, and KDE 4 didn't try to eat my
/home dir, nor did I try to prevent that after all.
Of course not everything is perfect, and I hit a very bad bug in Dolphin, KDE 4's lightweight file manager, which turns it into a time-bomb of sorts, crashing roughly after 1 minute of use. However, that bug doesn't affect good old Konqueror and that gave me an opportunity to go "whoaaah" and "ahhhh" and "ohhhh" at the various user interface changes in this version; for example, the previews of directories are much better than on the KDE 3.5 version of Konqui — now we have actual previews embedded on the directory icons, rather than little icon overlays. IMHO such feature belongs in the realm of eye candy, but there's still a fair possibility of revealing your pr0n stash if you navigate the parent directory with this enabled.
KDE 4.3's performance here is far better than what I experienced with a amd64 openSUSE-based LiveCD image using KDE 4.2.x. I couldn't know if this is because it's Debian, or because it's KDE 4.3, or because my custom kernel config rocks. Regardless, the laptop's battery still lasts almost the same as before upgrading to Squeeze — roughly 45 minutes. Of course, although I did enable some eye-candy to give radeonhd's XRender acceleration a decent work-out, I made sure that the new power management applet will turn it off when running on batteries. This is all very handy and beautiful...
But Squeeze lacks an important component for me, uswsusp, which provided some reliable work-arounds to get my laptop working fine both before and after suspending to disk (S4 power state). It is currently excluded from Squeeze due to some rather astonishing bugs, which means I had to seek other solution for suspending my pretty Linux system to disk...
And the solution in my case is the TuxOnIce patch, which surprisingly manages to bring the screen, keyboard and touchpad back to life — a feat that the kernel's built-in S4 support won't perform here. With this patch applied on top of an otherwise vanilla Linux kernel I now have a completely usable Squeeze system that supports all the hardware and software features I need.