I think the language you use is very interesting. "A website that I own" makes it seem like it's a commodity and not necessarily a product which you've put lots of blood, sweat and tears into building. From your description, it sounds like that's the case. So really its just a domain sale. Not sure what the domain is, so I can't be certain how much value that has in and of itself.
That said, the advertising profits alone do give the site value. I'd counter the offer at $600 and point out that, if current trends continue, the site will pay for itself in the next year. But there's definitely a lot of risk involved, so it's worth selling and taking the money now. I would at least.
Unless you want the domain for something, sell it. It's hard to rely on ad revenue. Being able to pocket a few hundred dollars right now is probably a good option.
It shouldn't affect load time at all. Don't load the preview until the user requests it. That's the one feature I thought was missing. Otherwise, it would be awesome. I mainly use iTunes to listen to preview, removing the step to go to iTunes for that would be awesome! :)
I completely agree! Though, maybe orientation toggling could be disabled on a system level. Double clicking the home button could bring up a dialog box allowing you to turn it off easily.