Moving plug-ins to another computer

I just went through this earlier this year. It was not an entirely pleasant experience. I'll relate some of the challenges I experienced...
 
You can start by simply copying your previous VSTPlugins folder to the laptop. You don't have to worry about overwriting the 64-bit versions of SONAR-bundled plugins, because they're in another location. 
 
After a re-scan, many of them will just work. But many, perhaps most, will have to be re-authorized. 
 
How much of a pain that is varies a lot from vendor to vendor. For example, Meldaproduction makes it very easy: just copy over the license files. FabFilter was almost as straightforward. Waves, as usual, was the biggest PITA.
 
Like you, I was also migrating to 64 bits. That meant having to download 64-bit versions of existing plugins. For the customer-friendly vendors (Valhalla, Melda, FabFilter, Voxengo) that was painless. Of course, a few had no 64-bit counterparts, but fortunately only one of my 32-bit plugins (SampleTank 2.5) failed in the 64-bit environment. I was sad to lose it and went as far as buying SampleTank 3 so I could import and continue to use the old libraries.
 
A few plugins see their 64-bit and 32-bit plugins as separate products. Ozone was like this. Every project I brought over from the old machine had to have Ozone deleted and re-inserted. I saved presets on the old machine using the names of the songs they came from, and copied all those presets over, which eased the transition. Most products don't have this problem, and SONAR is perfectly happy to load the 64-bit version into existing projects without complaint. I was relieved when Pro-Q dropped in without any fuss.
 
One sticking point was the few plugins that could not be re-installed because they were obsolete versions and no longer available for download. For those I had no choice but to remove them from old projects and replace them with contemporary versions. 
 
Whenever I'd load an old project, SONAR would give me a helpful dialog listing all the plugins it couldn't find. I'd press CTL-C to copy the list into a running text file, where I could cross items off the list as problems were resolved.
 
Altogether it took a couple weeks and $300 (for ST3) before I could pull over all of my old projects and run them on the new machine.   

Some really good tips --- thank you ! Yes the old computer is 32 bit. New one arrives on Friday - so soon will deal with these issues...    
 
Thanks !

I managed to migrate my Waves plugins (only AU's, tho I can't remember if those are the only ones I installed... might be).
 
Copied Applications/Waves folder, and everything from Library/Application Support/ and Library/Audio/ that pertains to Waves. I had the licenses already transferred to the new workstation so my DAW just loaded up without any issues.