In June of 2011 I bought a 128GB Crucial SSD. For 210€ ($270 USD)!!! Very expensive, but it is the best buy I've ever done, without any doubt.
And I'm not taking the best of it because my SATA bus just runs on 3Gb/s and not at 6Gb/s, and I have a data transfer of just 224MB/s instead of the 480MB/s that the hard drive provides. But I don't really care. It is astonishingly fast. The OS loads in less than 20 seconds (well, I usually have +10 days of uptime and I don't really swich off the computer), opening applications such as OpenOffice or Gimp is very very fast... I love it.
And today I have checked the new toys of Crucial and they are amazing! Look at that: SSD starting at 42€! And if you want a 128GB 3Gb/s SSH you can get if for 76€!!!
Ok, now let's talk about the capacity of the hard drive. You may say: "oooh! I can fill 128GB in a few ours, you know? I like to download random films (most of it is porn, and we know it), having installed all the games in the World and having more unuseful stuff in my hard drive there for ages. I don't know what's deleting... and that's why 128GB are not enough for me!".
Ok. I'll tell you something. If you are a normal user you don't need to have 25 horus of films in you laptop, 128GiB SSD is good enough. I promise. If you are running Windows is not that much, but it's fine. And you can have an external HDD and save there all the shit you usually downloads. You could buy the 256GiB HDD for 153€ but I think it doesn't worth it. Or maybe you can wait a year or two because the prices will get lower and lower.
I don't know if I have convinced you to buy a SSD, but I promise it worth it. Is like Internet in you mobile. When you have it one time, you cannot live without it. The next phone MUST HAVE Internet on it. If you don't have it then is not a mobile phone. The same with the SSD. I will never ever have other laptop or PC with a "normal" HDD.
Take care. Jan.