While it's certainly not a necessity, count me in as another vote in favor of better electronics. The 480 unit you have is good and will show you fish, cover and even thermoclines fine. I don't know of any unit that has barometric pressure (LOL), but I don't put a lot of stock in that any way. GPS and color on the other hand are both great features to have, along with the ability to read/record to SD/MMC cards. On the side reading deal though, I'm still not sold yet.

-T9