Advice wanted: buy my lease 2004 or '07 Explorer

I thought I'd get some input on this tough decision I have.

I like my '04 Explorer XLT. It has only 38k miles, runs great and I can go
ahead and buy it for a good price.

I also like, much to my wife's dismay, new toys. I would love to get an '07
Explorer XLT or Bauer. Have there been really big improvements on the past
three years? I'm not talking cosmetic, but rather ride and performance.

Also, I'm thinking of bitting the bullet, if I get new, and getting the Ford
GPS system. Any readers have any feedback on this system? The Ford site says
beans (from a technical standpoint). I'd also love it if the radio offered
Bluetooth phone support, but the site again doesn't state that.

Thanks in advance...