I run Ubuntu Linux on my desktop computer.

Music Player Daemon and Sonata (reference, my post)

Prior to switching, I spent countless hours organizing and adding metadata to about 60 GiB of music. I tired of Windows Media Player, Winamp, Foobar2000 and iTunes… especially iTunes. Many of those players are fine for people who keep thousands of songs in a single unsorted directory, but such disorganization would make me keel over. They completely fail to respect an already-ordered music folder.

The Ubuntu music players I tried—Rhythmbox, Quod Libet, AmaroK and others—didn't really satisfy me, mainly for the same reasons. MPD did. So far, my favourite client is Sonata.

• Install mpd and mpc using Synaptic.
• Open a terminal (Applications → Accessories → Terminal). I have my music in /home/khaeru/music, so I replace the MPD music directory with a symlink to my own:
  

  $ sudo rmdir /var/lib/mpd/music
  $ sudo ln -s ~/music /var/lib/mpd/music

• Download and install the latest Sonata .deb from packages.matt-good.net.

DNS caching (reference)

There are a lot of comments, but the best method boils down to:

• Install dnsmasq using Synaptic.
• Press Alt-F2 and run gksudo gedit /etc/dhcp3/dhclient.conf. Uncomment the line:
  

  prepend domain-name-servers 127.0.0.1;

• Press Alt-F2 and run gksudo gedit /etc/resolv.conf. Add as the first line in the file:
  

  nameserver 127.0.0.1

That's it. If you want to test it, open a terminal (Applications → Accessories → Terminal) and DNS lookup the same address twice:

$ dig wwwcomcom.com
$ dig wwwcomcom.com

The second number is usually 0 milliseconds, because the result is cached.

Hibernate and Suspend Buttons (reference)

For some reason my computer fails hard at suspending and hibernating—this happened even under Windows. To discourage myself from clicking the Hibernate and Suspend buttons:

• Press Alt-F2 and run gconf-editor. This roughly parallels Windows' regedit, only with less clutter.
• Navigate to /apps/gnome-power-manager in the left pane.
• Uncheck can_hibernate and can_suspend in the right pane.

The buttons disappear.