From this thread on SD cards, the comment from by carlosfm on Mon Aug 27, 2012 9:46 pm suggests that the 16GB Sandisk Extreme Class 10 45MB/s working fine on my Pi might be a good card to use.

Partway down the page, it says there's a debian package to download:

$ wget https://dl.dropbox.com/u/15710882/iozone3_397-2_armhf.deb
$ sudo dpkg -i iozone3_397-2_armhf.deb
$ iozone -e -I -a -s 50M -r 4k -r 512k -r 16M -i 0 -i 1 -i 2 | tee iozone_out.txt

I was reading the manual for iozone and it said to make sure, for accurate results, to make the -s switch size be TWICE your ram size. My Pi has 512mb so figured minus the 16mb gpu share I'd make it 1000M (for 1gb test file)

Still, there's more to learn. Something about:

just apt-get install bonnie++ 

(Source)

• changing the password: passwd
• updating: sudo apt-get update && sudo apt-get upgrade
• installing screen: sudo apt-get install screen
• sudo apt-get install alsa-utils; sudo modprobe snd_bcm2835; sudo amixer cset numid=3 1 to be able to listen to audio via the headphone jack. See here.
• Playing m3u playlists: mpg123 -@ http://streams.br-online.de/bayern3_2.m3u

They claim it's often a power problem.

Forum user MrEngman reported some keyboard repeats and wireless hangs until upgrading to the debian6-19-04-2012 kernel, which he reports stable with no problems even with a low TP1-TP2 voltage of 4.65 - 4.68 volts.

To see which version you have:

$ cat /proc/version

Try plugging the keyboard and mouse directly into the Raspberry Pi, and see what happens.