Great new purchase. I'm sure you'll get lots of use out of it as there are a number of readers that can read epub books. I don't think epub will be going anywhere soon even if sony brings out new readers. In the UK it's more difficult to get the kindle, but if Amazon does start selling it here I'll have to consider whether to get one. I keep telling myself I don't need two readers, but they have different advantages and I do like to try different things. (It probably depends on the my work situation over the next few months and whether sony does bring out anything new.)
Anyway, the 505 is great, and I'm sure you'll enjoy using it whatever else happens to ereaders