For $125, you can take your MacBook Pro, give it a fast SSD for the operating system, keep your existing hard drive for media, and pull out the DVD drive which you probably never use anyway and use it in an external enclosure. Amazing, huh?! The SSD can fit into the area designated for the DVD drive, which is where the magic really happens. Technically you can just stick it in there and rewire stuff yourself for cheaper, but using a mounted drive enclosure is a lot stabler and only a couple bucks more.
I just bought the components, and as soon as they arrive I'll be shooting a video of me tearing the machine apart and hooking it all together (this will be in another blog post, it will appear in the list of related links below). If you would like to follow along, just go to Amazon and buy the following components (prices accurate as of May 28th, 2012). Note, you only need one of the SSD's listed below.