I used to live by Old St. station (very near to Shoreditch) and I liked the area a lot. It was close enough to central London that I could walk if I wanted to (that said, I like long walks), and there are a number of cool markets in the area (Columbia St. flower market, Spitalfields market, etc) and tons of bars and restaurants. The one thing I would say is that it has been 'up and coming' for a little while now...certainly since I lived there in 2002-2003, so it's not all that cheap anymore. Certainly cheaper than central London however.
I would definitely check the places out in person. There are still some areas that are not very nice, and the area doesn't appeal to everyone. While it is slightly past it's prime, it's still very trendy, so you may be paying a premium to live in a trendy area. Not sure if that is something you are looking for or not.