The advantage of an SSD over a HDD is its small size, no heating problems, no noise, some what bigger durability, since it uses a chip instead of a rotating disc.
But SSD's are very expencive, there are good SSD 64gb for around 100 euro, but i think its better if you buy Western Digital Raptor.
It has 300GB and its as expencive as a 64GB SSD. Plus the speed is roughly the same, the only thing whats not the same is noise, heat, durability if not properly cared off.
If i had to chose i would have chosen the raptor HDD because of its storage space.