iphone 4s-----money invested or wasted?

I was planning to upgrade to a new iphone 4s...

I have been using the iphone 4 for like a year now and was impatiently waiting for the next release. When the iphone 4s came out I would admit I was a bit disappointed seeing the same iphone 4 hardware, until I thoroughly went through its new capabilities and specifications ecpecillay 'SIRI' & the camera. I was and I am still convinced that it is one of the best phones out there.

However when I was thinking of an upgrade from iphone 4 this is the picture I get in the back of my head

iphone 4--->sell--->then add some cash------->iphone 4s (iphone4+ SIRI + an AWESOME camera).

So I came out with another plan

iphone4----->keep---->use the extra cash------>get windows phone 7...try something new...THEREFORE...wait for next iphone's next release.

I beleive I have not wated my money and what I have done probably suits me. well what would you have done??