The last version of PHP 5.3.x was released today:
The PHP development team announces the immediate availability of PHP 5.3.29. This release marks the end of life of the PHP 5.3 series. Future releases of this series are not planned. All PHP 5.3 users are encouraged to upgrade to the current stable version of PHP 5.5 or previous stable version of PHP 5.4, which are supported till at least 2016 and 2015 respectively.
I’ve been happy with PHP 5.5.x versions. If you haven’t updated to 5.4 or 5.5 yet, now is the time.
If the WordPress.org stats are any where near accurate there are plenty of hosts that need to get working on updating PHP:
Some where in the range of 75% of sites are using PHP 5.3 or lower and should be looking to upgrade.