Should I still install a 32bit version ?

I used to install both 32 and 64 bit versions with Sonar 8, 8.5... in order to get access to some plug-in effects that used to work only in 32bits and would crash the 64bit version.
 
Now I have installed the X1 beast with Dimension Pro and expansion packs, and additional content, I wonder if I should install another 20GB with a 32bit version (for same reason) ?? (Especially that I realized that even Dimension has a 32 and 64bit version...)
 
Are there any alternative options (such as: would the 64bit Dimension work under a Sonar X1 32bit version , and vice versa?)
 
Gee I have been catched over the last few years with a 3-boot (XP, Vista and 7) machine, 3 HDD, always increasing the C: drive every time I installed an OS but it was never enough after a while... Now that I built a new machine and allowed 300 GB for the C drive, I'am already (after just a week) using one third of it with Windows 7 and programs (no data..) Of course I do have about 2 TB spreaded over 3 other internal and external HDD for data (audio or else).
 
Thanks,
Rob