I just bought an Intel 40GB SSD and played with it. Installed in on one of my i7 boxes. I needed to re-install Win7 OS to use the SSD as C: and my original platter disk as data storage.
My first impression: I have to say I didn't see much of benefit to me as far as speed. I did only 2 tests so far.
1. To start up TradeStation. I have 8 monitors with 40-50 charts, many with custom indicators.
On platter disk: 1 min 40 sec
On SSD: 1 min 29 sec
(only shave off about 10 seconds)
2. To reboot Win7.
On platter disk: 1 min 20 sec
On SSD: 1 min 7 sec
Only shave off 13 sec.
I read somewhere (I think) that rebooting Windows on SSD only takes like 20 seconds. I didn't see that happened on my setup. Wonder if I did anything wrong in setting up the disk. But I couldn't think of anything else I could have done.
To buy a SSD is extra expense, that's one thing. But the extra time needed to be spent in re-installing the operating system, customizing it, re-installing all the application software, migrating the app data (such as layout, pages, indicators, etc..)... it is a lot of work. If the SSD is useful in only speeding up reboot time (once every few days) or the app start up time (only once a day), it may not worth going through this trouble. Conceivably if will speed up program execution - if your program has a lot of disk I/O. Perhaps when back-testing (which I don't do). I do use a lot of indicators fetching and plotting data in real time. But I think my bottleneck would be more on the network throughput than on the disk I/O throughout the day.
So... to SSD or not to SSD... depends on your computing need.