Take recent filesystem development, for example. There's ext4, btrfs, unionfs and others. Especially btrfs sounds interesting for me because I really want something like ZFS for Linux. It would make deployment so much more failsafe: make a snapshot, deploy new realase, if something goes wrong -> rollback. The package manager in OpenSolaris, for example, uses ZFS snapshots in a similar way. Before the package manager installs new system packages it creates a snapshot first. This allows the user to boot into the previous state if something goes wrong.

Anyway, back to Linux! On the distribution side I learned about ArchLinux. And after playing around with ArchLinux for some hours I have to say I really like this one. It's somewhere between Gentoo, Debian and the BSD systems. Like Gentoo you can build up your own system and you decide what goes in - and what not. A big advantage, however, is that ArchLinux provides precompiled binaries. But for i686 and x86_64 only. Which is perfectly ok for me though. Also, ArchLinux is very up-to-date. Actually the most up-to-date Linux distro according to OSWatershed. Cool :-)