*EDIT 30/01/12* - Windows Experience Index now rates this as 7.5 out of 7.9 - my 7200 RPM Hitachi 250GB HDD scored 5.9 and itself was very fast.
I'm sorry but please just forget all the numbers for a minute, including the advertised 'Read' and 'Write' speeds, and all the other numbers. I've just installed this into my Dell Studio 1749 as the primary Hard Drive. I paid £66 for this, not on Amazon. I then installed Windows 7 64-Bit onto it, after formatting it and assigning it a letter so My Computer identifies it. OK...
Firstly, the installation was really quick. Within about half-an-hour, which is amazing, Windows 7 64-Bit was installed and ready, including the 2 or 3 automatic restarts.
Secondly, and most importantly, Windows 7 64-Bit starts up within about 20 seconds. From the Windows Logo, it's about 15 seconds. Anything you subsequently install on the OCZ SSD, well double click on it and it jumps at you, instantly. I've just opened the Start menu and clicked randomly on several applications - Solitaire, Control Panel, Help and Support - instantly they appear right after you clicked them.
Thirdly, copying or cutting and pasting movies or big games around is about 5 or 6 times faster than my old HDD. Even transferring files to and from external HDDs being limited by the other HDD's transfer rate is still about 2.5 times as fast.
Yes, we all know SSDs are expensive, but you know what? If I can open up my laptop thinking that I am never going to be annoyed by random pauses and loading times of applications, and things conflicting, and then more waiting - the fact that I won't be staring at an annoying blue circle going round and round forever or, if you're on XP, where it would be even faster because it's lighter on system resources, that hourglass which keeps flipping around as if to makes the ridiculous loading times aesthetically pleasing, then I am utterly sold on this. And believe you me, it is fast, stupidly fast. Just forget those numbers, you install this SSD, you will be sold, and I guarantee that.
This is undoubtedly the best upgrade I have ever installed on my laptop, by a very long way. It will make a huge difference.
NB. You may have to buy something called an interposer which slots into the SSD and connects it to the area on your motherboard or laptop board. Usually if you take out your old HDD there will be one attached to the motherboard anyway. If you have a spare HDD bay on your laptop, then you may need another laptop-specific caddy to hold it in place.