If the device works, even if the GPS isn't the best, to me it's still much better than carrying around two things, having to charge two things etc. Nothing is stopping you from getting a separate device, but there's no reason that it shouldn't be integrated if it's done properly. I'd rather have a crappy integrated GPS in my treo for tomtom than have to carry around an external one, even if the external one had "more features" (what features do you want in a GPS anyway?). Again, even on the 810, you can use an external GPS if you want to, but the fact that it has one built in is very useful.

If you were happy with your n800 how it worked, and what it did, and it had a phone built in, you wouldn't NEED to replace your phone, would you? I've had no need to upgrade the phone in my treo because it works as part of the system that meets my needs. I'll never need to replace it, until I replace the treo. If it stops working, I take it back and get a new one, generally for free, and even if not, quite frankly, a couple hundred bucks for a new treo is still pretty cheap, given what it does and compared to how much my monthly cell phone bill is.

This argument could go on and on and on, but camera phones are popular, even though the pictures suck. Laptop webcams are popular, even though video quality stinks. Built in wireless in laptops is popular, even though it may be B/G instead of N. Laptop hard drives are slower and smaller than desktop ones. It goes on and on and on. Compromises are always made for size. The logical conclusion to your preference is to carry an external wireless N card, a HD video camera, a digital SLR camera, a military grade GPS, and an external raptor HDD with you just because it's marginally better for some things than the ones built into a laptop and camera phone. That's a perfectly valid thing to do, but it totally defeats the point of devices like the NIT, IMO. Take the camera off of it, GPS out of it, WIFI out of it, speakers off of it, bluetooth out of it, FM radio out of it, kickstand out of it and put them all in separate external devices, and what do you have?

I love gadgets as much as the next guy, but I see no point in dragging more of them around than is necessary just because you're afraid of having parts of them break.