The recent release of PostGIS 2, the spatial extension of Postgres, has been a huge benefit to geo software. It has increased the ease and speed at which we can now work with large data sets and do spatial computation on them.

My favorite part of PostGIS 2, besides much of the cleaned up syntax, is the new Geography datatype. It has the spatial projection built in to it, so it automatically does great arc computations. Before we had to write more clunky SQL to achieve this. Was a significant barrier for my learning postgis, which has now been removed.