To answer this question it will depend on if you want to use an ICS or JB ROM. If you want an ICS ROM, I will tell you to look into AOKP Milestone 6. If you want a Jelly Bean based ROM I will tell you to look into Euroskank's CM10 builds. They are nightly builds so they are update uhh nightly .
Have you already unlocked your device? If you haven't that will be your first step. All the ROMs that will be recommended here will be ones compatible with the Verizon Nexus (why we are in the VZW Nexus section ).
One more vote for Euroskank. Separately, I'm supremely satisfied with JB on the whole. Does everything ICS did more fluidly and adds a few new features which are all pretty handy.