Do you WANT a 17" notebook?? I had a 17" HP Pavilion and it was a big, heavy beast. If you want to use it primarily as a desktop replacement then get the 17".
You can go in between and get a 15" on eBay for the same price point (around $1200-1300).
The i7 13 is a nice machine, but if you want a big screen you might be a little disappointed. The 13 is like a cell phone display compared to the jumbotron 17