I prefer ArchLinux. Its _the_ best OS available.
Its extremely easy to use (once you learn to love its commandline that is).
Everything is highly organised and configuring it is a pleasure.
Software run blazing fast even on my 256MB RAM.
Unlike windows, I have no performance issues or fear of viruses and other security vulnerabilities.
For me, resources saved are resources EARNED. I used a friend's fresh OEM vista machine with 1GB RAM and E4600 CPU. The RAM is 4 times mine and the CPU is 4 times as powerful as mine. It still took 3 minutes to start and be ready for use, while my system boots and the desktop opens in a total of around 40 seconds.
I see no point in an OS like vista which hangs while opening multiple tabs in IE, almost as much as firefox does on my ancient PC running archlinux.
Compared to other Linuxes, I think Arch is the best binary distro around. Its install speeds are awesome, and I don't need to install newer versions of the OS like in Ubuntu because its a rolling release distro, in the sense that software is constantly upgraded, released on the same stream. Effectively, this makes ArchLinux, a distro almost as old as Windows XP SP2, a ZERO maintainence distro.
For people with powerful rigs, Gentoo beats 'em all, but spending whole nights compiling on an ancient Pentium 4 2.66GHz CPU is not some thing I enjoy (Though I am moving to gentoo once I get my Quad Core Phenom II 910 rig
). I dislike Ubuntu because its becoming like Windows Vista. Unusually slow compared to its peers. I think its just my 256MB RAM, because it performs great on a friend's 1GB RAM system with a Pentium 4 1.7GHz CPU. But whatever be the case, I think I just outgrew it.