Re: Which distro do you run and why?
I use Crunchbang because it's lightweight, and my laptop has a Celeron 900 processor. I also like that it's more-or-less just Debian with an extra custom repo, and it comes ready-to-use OOTB, even with Openbox. Plus, Crunchbang's forum is filled with helpful, friendly folks, and it's just a great atmosphere.
I'm considering a move to Slackware (I've used it in the past), but I've been spoiled by APT's dependency checks, so I'm a little wary of the tedious package management, though I'm aware that Slack's package management has advanced a bit since I last used it (in 2004), even if it requires a third-party package manager.
I've also enjoyed Mageia, but it didn't have all the packages I needed, so I had to go back to Crunchbang since the Debian repos have everything.
I tried installing Funtoo (founded by Gentoo's founder and based on the Gentoo principles but with better package management and other tweaks) on an old P3 866MHz computer, but I couldn't get it to boot (some problem with fstab, even after I quintuple-checked that it was correct). I may try it on my laptop if I have a free weekend, but it's a lot of work if I have the same fstab issues.
I'm also watching MauiOS, which is the first distribution I've heard of to make the switch from X to Wayland (actually, it never used X, so there's technically no "switching", but relative to all other distros, it's a switch). It's a bit slow and buggy right now, but I'm excited about Wayland.
One of the lightest-weight distros to run is actually Crunchbang. I think as shipped, the OOBE RAM footprint is about 100+MB in size. For modern distros, I don't know how to make it any lighter-weight than not shipping a GUI at all.
I agree 100%. Mageia and Fuduntu gobbled up to 300MB of RAM at boot for me. Crunchbang uses <120MB of RAM at boot, and that's with composting and other extra stuff enabled. And if you really want, you can get rid of the Crunchbang repos from sources.list, and it becomes a generic Debian that's already been tweaked and made usable.