For my less geeky readers, a Solid State Disk (SSD) is similar to the mechanical "hard disk" which has traditionally been the storage in most PCs and laptops. However, an SSD has no moving parts and works entirely off memory chips - a bit like a USB memory stick. The big advantage of them is they're a lot faster to read data from than a mechanical hard disk.
SSDs have been standard issue at work for a while now, but I hadn't yet had occasion to buy one myself. I was pleasantly surprised by how much of a price collapse had taken place - I picked up a 250GB SSD from Ebuyer for £64. The use-case was my home desktop PC, which was glacially slow at resuming from hibernate, and struggled to run Windows under VirtualBox. A Core2 Duo should have no problem with this from the CPU side, but it felt like I/O performance was the problem.
I was surprised by just how small and light the SSD was - of course, with no moving parts or motors to spin the platters, it's about half the size and a tenth the weight of the equivalent mechanical disk.
Since the SSD was the same size (250 marketing gigabytes, which is to say 232.9 actual gigabytes) as the "spinning rust" it was replacing, I simply connected it, booted into SystemRescueCD from my network boot server, and used dd to copy the block device of the old disk over onto the new one. It looked like it was going to take about four hours, so I issued a shutdown for five hours hence and went out for the day.
Having now had a chance to try it out, I'm properly impressed - the machine boots and resumes much faster and Windows under VirtualBox is now snappy enough to be usable. At that sort of price, I shall have to see about getting one for my laptop too.
Update: some good discussion on social media. The downsides of SSDs are pointed out, e.g. limited write capacity (if you were to write to this one continuously for 2.5 days, you'd wear it out), and that they aren't suitable for archiving as power-off data retention can be limited to months. None of this matters for my use-case, but enterprise-grade SSDs with enterprise-grade price tags also exist to try and solve at least the write lifetime issue.