Multiple installations of minecraft?

Is it possible in any way to have it so i can have multiple installations of minecraft? Per say, one vanilla, one with mods on 1.6.4 and one with mods on 1.7.2?

Of course; the Minecraft launcher defines multiple "installations" as profiles.

When you launch Minecraft, on the launcher, click 'New profile' and define the version to be loaded there. Once complete, select that profile and load it up as you would normally to play the selected version. Using this, you can have multiple profiles stored on your computer all under the same account.

A detailed tutorial: http://www.modgician.com/creating-editing-profiles-new-minecraft-launcher.html

You will be able to create/load profiles for both modded and vanilla Minecraft. Making a mod-compatible profile is a little extra work, but once it's set-up it usually works just fine.