I have Windows 7 x64. What version of Sublime Text 2 is better to use? Are there any disadvantages to using ST2 x64 compared to 32 bit?
Why I ask? for example Total Commander is better to use a 32-bit even on x64 OS since on the TC x64 version there is an incompatibility with some plugins.
I’m not aware of any disadvantages, and the advantages are the same for all 32 vs 64 bit software. 
64bits environments are much, much better, faster, and they usually support 32bit software as well so no worries there.
You can read up on the subject here:
lifehacker.com/5431284/the-lifeh … ng-systems
Does this answer your question?
The only difference in the bits here might be the size of a file you can open. For example some editors in 32bit may only be able to edit a 4GB file at once (or some insanely large size of a file for text) while 64bit can handle much larger file-sizes without worry (except speed of course.)
Since you’re on 64bit, go with 64. There are no known compatibility issues here that I know of since all the plugins are written in Python on top of ST and ST is written well enough so there aren’t any issues between versions.