Installing on SSD to improve load times?
Yes it will help load times. It will also help with your OS boot as well. Try to shoot for AHCI mode and not just IDE.
This is a simple explanation of the differences between the two:
http://www.diffen.com/difference/AHCI_vs_IDE
intel 335 180gb/intel 320 160gb WD 3TB Gigabyte GTX G1 970 XFX XXX750W HAF 932
If you get an SSD and you have the 6Gb port free use it, the difference compared to your Sata drive there is night and day, my load times into LA on my SSD are about 5-8 seconds depending on time of day, WvW and other load times are all under 10 seconds,
The load times can also be slowed down by the server lag, espically if your spawning into a big event or somewhere where there are alot of people standing about, ( LA for example )
As for OS loading times, it will be faster depending on your system setup, remember your system is only as fast as the slowest part.