I haven't upgraded my computers in a couple of years now and have been watching SSD for quite awhile for it to come down in price. I was sceptical for a long time about the performance increase these would have. There are a few things I hate about computers now days: Boot time, time after boot before I can start using programs, and latency when clicking something. I've never really achieved "real world" faster performance in those areas from a CPU or RAM upgrade.
This week I finally bit the bullet and purchased two Crucial M4 256GB SSD drives and put one in the laptop. The other one will go into my desktop soon. All I have to say is that so far, this upgrade blows away any other upgrade I've EVER done to a computer. My laptop would take about 1:15 to load to a state where I could start opening applications quickly. Now it takes 25 seconds to get to the desktop. From there I can instantly start loading programs without waiting. Chrome and Photoshop load like they have been running all day. I've made a quick video showing how fast it is (SEE BELOW).
I cannot believe how much of a difference SSD made, and this is on a 5 year old laptop with a C2D 2.2GHz CPU and 4GB of ram running Windows 7 x64. I can't wait to put this on the main computer now as my laptop specs aren't even that great.