Hi idlebones! I used to have that problem. What is happening is that you might have different versions of the jre installed and it defaults to the 32 bit version. This is what I have installed on my windows 7 machine:
Java(TM) 6 Update 29 (64-bit)
Java(TM) 6 Update 30
Java(TM) 7 Update 1 (64-bit)
When running eclipse for the first time it can not find the 64 bit environment and I believe it tries to use ( Java(TM) 6 Update 30 ). Below are the steps to the fix:
1. Navigate to your eclipse install.
2. Open your eclipse.ini file.
3. Open the .ini file with wordpad (wordpad is organized better than notepad).
4. input the lines below and click save.
-vm
C:\Java\JDK\1.6\bin\javaw.exe (This is an example. Your 64 bit version path may look diifferent)
I have mine pointing to the 1.7 java version. I hope this helps.
For more info:
http://wiki.eclipse.org/FAQ_How_do_I_run_Eclipse%3F