I know the feeling. I purchased HB 777c and a HB 565 last year and now I am kicking myself for not purchasing a HB unit that was GPS ready and able to use SD cards for lake maps.
I love my HB 777c unit with the 4000 watts and the number of pixels. I bought my 565 for the front of the boat and love it. That one also is loaded with pixels.
I would buy the 787c2 if I could do it all over again.
Have fun shopping.