This is the first time I've tried to used an SSD on a desktop, and it was primarily to try to speed up Windows booting and application start. In short: don't bother.
I experimentally bought a small but relatively high-end SSD: Mushkin 60 GB Deluxe, with the Sandforce SF-1200 controller, to be used as the OS disk drive. I could have bought a bigger one but really didn't wan't to experiment too much on my own money :)
About the device itself, I have mixed impressions:
- The raw performance numbers are as advertised. Running the benchmarks I really do get the impressive 250+ MB/s and high IOPS numbers
- On the other hand, I apparently had compatibility problems (or the device was more broken than I thought): it took a long time to initialize after a cold boot - the BIOS usually couldn't detect it before rebooting the machine again
- "IRL" performance in Windows was - disappointing. Yes, it was faster (especially in the benchmarks, as I said) but not where I wanted it to be - in starting and running applications. I got nowhere near the responsiveness I thought I would get with the thousands of IOPS the machine is capable of. While in FreeBSD it's ridiculously obvious with seek-intensive operations (like pkg_info...), here it was a surprisingly "meh" experience. Faster: yes, but "actually visibly fast" - no.
Finally, the device apparently died after a few days of use so it kind of settled the things for me. I don't think it actually physically died, but its firmware got wedged so that it doesn't respond to inquiry any more, and as so it cannot be detected by the BIOS any more. Effectively, it's dead either way.
I'm planning to get it replaced with a WD Caviar Black 1.5 TB.
Update: And so now I have "rotating rust" capable of 140 MB/s burst bandwidth... IOPS still sucks :)