I bought a ocz 64gb vertex and i have been very pleased with the speed of my pc since. I paid £160 for it and the very next day the vertex 2 was released for exactly the same price (nearly) and double the write speed. :|
If i had to buy now i would buy the vertex 2.
You get so used to the SSD that when I go to another PC running off SATA it feels so slow. But to your question. I am not sure if there would be a visible difference between a vertex 1 and vertex 2. As the load times on vertex 1 are already super fast, so photoshop loads in 2seconds and on the vertex 2 is loads in 1.5seconds for example. But it is one of those, you might as well get the vertex 2 with the super write speeds.