13" Macbook Pro Retina -- buy now or wait for the refresh?

Hey Apple Core,

I've been wanting to get a Macbook for years, and now I'm finally in a financial position to do so. I currently don't have a laptop at all (just a desktop and an iPhone) so it would be a pretty big convenience to have one, although I suppoaw I could wait a while longer if I had a good reason.

Here's my question. According to the MacRumors buying guide, the average Macbook Pro refresh lasts 166 days before being replaced. Right now we're at 97 days, or about 60% of the way there. However, the last cycle lasted 251 days. From what you guys know, is the next refresh likely to be worth waiting for? I know some of you must be following Intel and Apple's roadmaps more closely than I am, so I'm interested in your informed opinions.

In case it matters, I would likely be getting the 2.6 Ghz i5 with 16GB of RAM and 256GB SSD at $1799, and I plan to keep it for at least 4 years. It will be my main computer and will be used for everything from web browsing to light gaming to software development.