`sudo make install`<p>AFAIK if you enter `sudo checkinstall` instead, it installs into your package manager so you can remove it more easily later.<p><a href="https://help.ubuntu.com/community/CheckInstall" rel="nofollow">https://help.ubuntu.com/community/CheckInstall</a>
I switched to 1.9 for several greenfields projects. The postgresql gem builds cleanly, as does thin, which can be used in place of mongrel.<p>The biggest gotcha was having to modify my application to explicitly open text files in UTF8 mode. But the more than 100% execution speedup was a nice upside.
I reverted to 1.8 because I could not find documentation for the Standard Library of 1.9. Generating it myself also proved impossible (out of memory errors and other issues).