Personally, I find SSD's a bit gimmicky at the moment for a couple of reasons.
1. Lack of size. Really all they can be used for at the moment (if you don't pay an arm and a leg for say a 256GB SSD) is just the OS drive with a few applications. If your into gaming, like I am, the latest games will quickly fill up a small drive which means users often have a larger "normal" HDD for extra storage. This in my opinion defeats the purpose of having an SSD. Sure your OS will be nice and zippy, but the game itself will still be stuck at a slower speed when loading textures etc. As the saying goes, your PC is only as fast as your slowest component.
2. Drive wearing due to a limited amount of write operations a memory chip can handle, which means moving the swap file off the SSD. Again like above, you still need to have a slower "normal" HDD to perform this operation. Really not ideal if you want the best performance.
Still waiting for the day you can completely replace the spindle drives. Give it time. I was just reading Intel has plans for a 600GB SSD by the end of 2010, so give it a few years and we'll be there.
In saying all this though, I'm planning to go SSD in the near future when things improve. I've seen first hand just how fast these drives go and it's jaw dropping. You think one SSD is fast? I've built high end systems at work with a couple of SSD's in RAID 0. Now they SCREAM! Would love to do something like that, but just one downside related to one of my points. Trim at this time is not supported in RAID.
Like I said, they eventually get there....
