I've looked at this drive:
Crucial V4 CT256V4SSD2CCA 2.5" 256GB SATA II MLC Internal Solid State Drive (SSD) with Easy Laptop Install Kit.
Seems like a good choice for my system, compatibility wise (SATA 1).
$170.00 is cheaper than others faster drives, SATA 3 performance could mean incompatibility, if I'm not mistaken.
I installed this Vertex 3 SSD.
Restored Windows from Recovery DVD.
Windows Experience Index went from 5.1 to 6.4 (SSD is 7.6).
Boot time went from 150 seconds to 30 seconds including password entry.
Will tune the system later on.
Thanks for reading