Which DSLR?

[Seriak]

Okay, I originally purchased the first Canon DSLR years ago. (300D) I thought it is about time to upgrade. I only take hobby pictures, nothing professional. I have a few questions for you gurus.

1) Are my original lenses worth keeping. I see that all the new lenses have IS and possibly other improvements. So should I buy the body with the new lenses or save money and use my old lenses.

2) I was looking at the 70D. Is this a good choice or is their a better one to look at.

3) For macro lenses is it worth spending twce the money for the IS lense (Canon EF 100mm f2.8L Macro IS USM) overtop of the the regular lense (Canon EF 100mm f2.8 USM Macro)

4) Best place to purchase the camera and lense. Camera store, bestbuy, future shop, online vendor, etc.

Thanks in advance.