I have been using mechanical HDD's for years, but the new system i just built has windows 7 - 64bit on a Samsung- 830 series SSD, and there is quite a massive performance increase.
My system shuts down in about 2.5 seconds and starts up in about 8 seconds. Windows and all programs seem to load in the blink of an eye. It really is quite impressive.
General computing tasks are instantaneous, i don't think i've had to wait more than a fraction of a second for something to load. Definitely recommend the switch to SSD, especially if you are running intensive programs all the time.