I had almost the same experience. I had a 2007 MacBook Pro and one day dumped Firefox for Chrome. the difference was amazing.
I eventually did upgrade to a 2010 MacBook Pro/8GB/SSD. It came put to just under $3k after taxes. Expensive, yes. But the speed difference is amazing. It completely changed my work and productivity. Using a computer 8+ hours a day, it is easy to forget how much time you loose a day/week/month waiting on app to load, files to open, etc. The 2010 MBP (with SSD) is the nicest machine I've ever worke with.
I've heard Apple's SSD drives are expensive and there are better options, like http://eshop.macsales.com/shop/internal_storage/Mercury_Extr...