I have a laptop of that era (2008 HP Pavilion, Athlon64x2, 2GB RAM, 100GB HDD). It runs the Trinity Desktop Environment, which works just as well now as it did when that laptop was a flagship machine. (Updating a Gentoo system running on a machine that old is a bit time-consuming, mind you, but that isn't the DE's fault.)
I've tried several of the other lighter-weight DEs—XFCE, LXDE, Lumina, Gnome2 before it became MATE—but TDE does what I need it to do, and (just as importantly) the development team prefers to work on features and compatibility rather than tearing out things that still work or forcing new paradigms that don't really make sense for my use case onto me. It's there, it's solid, and I've already learned its quirks, so I can save my brain cells for learning useful features in other programs rather than having to figure out where the control for some bit of the GUI ran off to this time. Why would I use anything else? The thing I want most from my DE is for it to stay out of the way and not keep me from using other software.
(Plus, Konqueror may no longer be useful as a web browser, but it's still a better file manager than, say, Thunar, which I found to be a pain in the arse when I tried XFCE.)
I prefer mplayer—novel-length man page and all—for video, but there's nothing innately wrong with VLC. I did try it, a very long time ago, but it felt too GUI-oriented for my taste back then.
(I can think of exactly two times mplayer has failled to play a file I presented it with, and in both cases it was my own fault for not compiling in support for that codec. However, the man page is justifiably frightening.)