A hybrid option for you, if you have time to kill now, would be a dry run knowing that you would be doing the "real" switch to Windows 7 when you acquire your licensed copy in October.
Create a second partition, download all the necessary drivers
and do a test install. If you use the RC 7100 there is a greater risk of driver
incompatibilities/system quirks than if you use one of the "leaked" 7600 RTM versions. But you can discover what, if any, problems there might be with your hardware/drivers and what the solutions are (keep notes!).
It would not be necessary to install all of the 3rd party apps just to test for basic system level issues and verify the solutions.
The danger is that you will get too attached to the dry run install!