I think the home/student version is a one off purchase, and you don't get the updates when new versions come out.
Pro version (which I recommend you go for) you get updates when new versions come out and when you need to renew in 12 months then you can get a discount on the renewal.
Business version, well I made that mistake thinking for the same price as the Pro I get more features. But when it comes to renewing it in 12 months they don't give you any discounts.
The business version is only good if your business is paying for it, and if you have multiple Mac computers in your office and your IT admin guy is managing the licences since it allows a management console.
My recommendation is to get the Pro version if it's just for 1 Mac.