Yes, I know, I know, you are safer than instawallet while being equally comfortable - in fact, I can tell that simply from the fact that you don't have private key exposed in the link (which was bug-ass retarded thing to do on instawallets part).
You also know how to write a non-retarded robots.txt right away (something instawallet had to learn very late in its lifecycle).
I give you a B+.
Now, what other features are you going to have, besides breathtaking ease of use ? Because mere ease of use isn't quite enough nowadays
P.S.:
While I am not particularly fond of litecoin, I think you should support it, since it seems simple to do and would benefit your service.
I wanted to suggest namecoin, but since it committed "squatter suicide" it is now completely irrelevant... so, no need for disturbing namecoin's undead remains
