A little more than one year ago I purchased a 256GB Crucial SSD drive, the CT256M225, from Newegg for $639.
Setting the drive up initially was a snap. I installed Windows 7 on the drive, which automatically detected it and enabled TRIM support. Not really knowing much about SSD drives, I did some research into the optimal settings, and at every turn, found that Windows had automatically detected and enabled the correct setting. There was literally zero configuration required on my end.
Obviously, $639 at nearly $2.50/gigabyte is a rather steep price to pay, so my chief concern was reliability. After a year of 24-7 uptime and heavy usage seven days a week, logging 8,768 hours powered on and just 6 reboots, I can safely say that concerns about modern SSD reliability are unfounded. The excellent CrystalDiskInfo reports that the drive is still 67% healthy.
Everything I've learned about SSD's suggest that their failure modes are not catastrophic like spinning-disk drives, but that blocks will transition to read only. Given the time I've been running the drive, I suspect it will last another two years without serious issue. Economically, this means the drive will cost me just a bit over $200/year.
From a performance standpoint, transitioning to a SSD drive has yielded the single greatest performance improvement I've experienced for any hardware upgrade, ever. I think that the upgrade was worth every cent, and was happy with it immediately, though I was somewhat concerned that the drive would only last a year. Now knowing that it will almost certainly last three years, I feel that it was a bargain.
If you don't have a SSD yet, you should seriously consider one. I was looking to get a second CT256M225 for my development virtual machine, but found that it's since been discontinued. Fortunately, it's been replaced by the C300 series which sports 355MB/215MB read/write performance compared to the 250MB/200MB offered by the CT256M225, at a reduced price of about $475. That's $165 less than I paid a year ago, about $1.85/gigabyte. Crucial is also offering 128GB drives, and 64GB drives for about $240 and $140 respectively.
If this trend continues, in another year the price per gigabyte could be as low as $1.20, yielding a $300 256GB drive, or a 512GB drive for right around $600.
I've had a great experience running my entire system, operating system and software off the 256GB drive, with a 2TB spinning disk used for large file and virtual machine image storage. If you're budget constrained, I think it would be well worth the $140 to pick up a 64GB SSD for your operating system and critical applications. I think even this usage would provide substantial, noticeable performance improvements.