Deciding to use APT to maintain your software is really a no-brainer if you are Debian based. I prefer Ubuntu myself and its repositories has a lot of toys in them but for stability reasons they often do not hold the very latest versions.
Earlier today I was looking for an alternative repository for Redis and luckily I ran into Dotdeb. They have a bunch of nice packages, always up to date with the very latest version.
Installation
In order to get in on this goodness you must first add the Dotdeb repositories to your APT sources. Create a new list file in /etc/apt/sources.list.d/ and fill it with the following content.
# /etc/apt/sources.list.d/dotdeb.org.list
deb http://packages.dotdeb.org squeeze all
deb-src http://packages.dotdeb.org squeeze all
Then you need to authenticate these repositories using their public key.
wget -q -O - http://www.dotdeb.org/dotdeb.gpg | sudo apt-key add -
And finally, update your APT cache and install Redis.
$ sudo apt-get update
$ sudo apt-get install redis-server
Happy key-value-storing!