SSD's make your MacBook incredibly responsive, but I think the silence is as awesome as its speed. Actually I was a little worried and wondered if mine was working properly because it didn't make any noise.
I'm pretty sure in 10 years someone will start a thread and say, "I bought an old MB off of eBay and it keeps making a weird noise!" and others will respond, "Back in the good old days, sonny, laptops used to make a mechanical sound."