These are some quick thoughts about the installation.
SublimeText downloads a usable binary, but there's no automated way to get it into the application launcher menu (which I believe needs creation of a .desktop file). Fortunately, a Web search turned up both some .desktop files for SublimeText and something even more convenient: a PPA that automates the whole process.
RVM and Zsh also installed easily. I also installed GNOME Terminal (because it's more configurable without resorting to editing config files) and App Grid (because Software Center is slow and crashes).
I tried to install PostgreSQL 9.3, but kept getting postgresql-common version conflicts. After a lot of time wasted in Web searching, I finally wound up forcing compatible versions by doing sudo apt-get install postgresql-client-common=154.pgdg12.4+1 postgresql-common=154.pgdg12.4+1 postgresql-9.3. Why did apt-get have to be so boneheaded? Why couldn't it determine that version 154 was available in the sources it had?
PGAdmin installed well, and I was able to use it to connect after configuring the Postgres superuser to have a password (why isn't Postgres installed like this out of the box?).
I also installed gitg, which looks like a nice replacement for GitX on Mac OS, though I'd prefer that the branches were in a sidebar, not a menu.
Ruby gems mostly installed as expected. I had to install the libxml2-dev and libxslt1-dev packages to get Nokogiri to build, and Curb (unsurprisingly) required libcurl4-openssl-dev. The pg gem, of course, required libpq-dev so it could talk to Postgres, and RMagick required libmagickwand-dev.
At this point, VM performance was getting kind of bad, so I raised the RAM to 1.5 GB. Hopefully that will help.