Thanks for the replys. I am going to demo some bikes this week. I am tempted to go old school 26″, its just the resale value I fear in 2 years time when I normally feel like a change, it might be like having a cassette player in your car now!!
I shouldn’t worry about it. Unloading a 26″ bike might be an issue right now as there seem to be a lot of people like you who worry that it will become obsolete. But, in a few years time people will realise that 26″ bikes aren’t going anywhere and it won’t be any harder to shift than any other bike.
I do wonder whether all these competing standards aren’t just a way of trying to kill off the second hand market though. Chances are that whatever bike you buy now you’ll struggle to buy new forks or wheels for in a few years. It doesn’t mater what size they are, but they’ll probably have changes axles or brake mounts or something again by then.