On the dell inspiron 5000e with 320 megs of ram, I ran into an interesting phenomenon with pcmanfm. If I allowed pcmanfm to manage the desktop wallpaper and produce desktop icons, I ran into a spike of approximately 15 megs of ram usage and general slowness while scrolling.
I'm not sure what the correlation is, but when I switched to feh to handle the wallpaper and disabled desktop icons, scrolling became smooth once more. Weird eh, as even when I have other applications using up more memory than pcmanfm did while handling the wallpaper and icons, scrolling was still nice and smooth.
For those times when I simply want a dock instead of a full blown panel, I installed stalonetray, and it works great. It puts out a memory footprint a full 5 megs less than fbpanel, which is quite a nice improvement. It's not a big deal on this laptop, but if I were more memory constrained, I would definitely ditch fbpanel for stalonetray.
I've also grown to really love pysolfc as it has so many card games that it's insane! I can't count the number of hours I've spent playing this while watching tv or talking to the girlfriend. =p
The custom kernel I built is working great. It utilizes pentium 3 coppermine optimizations and I can really tell the difference in speed over the stock ppro kernel. I also cut out a LOT of cruft from the huge.smp kernel and slimmed it down big time. This was quite interesting as I noticed almost no difference in speed in my two faster boxes that run slack (a 1.86 ghz celeron m with 1.5 gigs of ram and a 2.4 ghz core 2 duo with 2 gigs of ram) when customizing the kernel. I guess the optimizations are most important on slower processors.
At this point, I consider this project pretty much closed. I'm very satisfied with the performance of this old laptop and see no need to upgrade this box further. I was considering buying another 256 meg stick and maxing out the memory, but quite honestly can't justify it. If I wanted to run gnome or kde, then I would probably do so, but with the way the system is set up right now, there is really no point.