Glide ratio: how much does it matter?

Stepping up to a higher performance glider or switching to a race harness could earn you a better [glide ratio][1] by 0.5 point. But what does this actually mean in terms of flying cross-country in the UK? I decided to investigate the theoretical answer with a few "back of the envelope" calculations. And I discovered that—on the average glide in the UK—*a 0.5 pt inferior glide ratio will cost you only one circle in the next thermal*.

[1]: http://en.wikipedia.org/wiki/Glide_ratio "Wikipedia entry"