Which version of Parallels are you running? After upgrading to Parallels 7 i found I never needed to boot into my Bootcamp partition ... i'm running suite of Autodesk products (Revit, Navis) plus various Win-only IFC tools perfectly well in Parallels and the integration back into the Mac environment is pretty seamless (e.g right-click on files in the OSX Finder, 'Open With' and it includes your Parallels apps in the apps available).
After a month of not using Bootcamp I migrated that partition completely into a VM and removed the Bootcamp partition. I think the performance hit is negligible for nearly all tasks - e.g my Cinebench results in Parallels are not far off those for the native OSX Cinebench, allowing for me not dedicating all cores to the VM which i found surprising
cheers,
os
cheers,
Owen Sharp
Design Technology Manager
fjmt | francis-jones morehen thorp
iMac 27" i7 2.93Ghz | 32GB RAM | OS 10.10 | Since AC5