I do trash them, but was just curious of what they have in them.
And yes, hovering over the links can be a clue, if it asks you to click on the link to update your details... and yet it goes to some unusual foreign country (based on the country code prefix in the domain).
But the ones with zip attachments, usually have the right homepage links in the emails (like this latest Groupon one)... because they want you to open the attachment, not go to the website. And if you did check the link, you'd end up thinking it was a legit email because it went to the homepage.