Garmin Quest
I have a Garmin Quest. Its a great unit, and it does everything I could need. And it's priced reasonably too (I found it online for about $250...and that was last summer).
The standard Quest mounting option is a suction-cup for the windshield. But I absolutely hated it being up there for several reasons: 1) it obstructed some of my view of the road. 2) it was difficult to reach when I needed to enter/adjust a route or address (I had to lean forward in my seat just to reach it) 3) I didn't like having the power cord running right down the front of the dash to the lighter plug and 4) It was too much of a pain in the rear to un-suction it and hide it from view whenever I left the truck (it really stuck out like a sore thumb up there on the windshield...a thief's dream!!)
So, I looked for various options including in the cupholder and/or in that little cubby behing the cupholders, but those were too far down and I had to glance too far away from road IMO. I also looked into the sunglass holder area, but I found that view to be too high for my liking.
Then, I came up with this spot:
It sticks into my tape player slot. I don't think I have EVER even used my tape player for playing music (I honestly don't think I even OWN any tapes, for that matter), so it wasn't a tough decision to sacrifice the tape playing ability. In this spot, I'm still able to view both the radio and A/C displays. The station pre-set buttons are a bit tough to reach, but I typically use the steering wheel controls, so its never been a problem.
I modified the Quest mounting bracket and attached it to a blank tape like this:
The tape slides right in and actually "clicks" into place just before the auto-load mechanism starts to "grab" the tape. I even unscrewed the 2 halves of the blank tape and filled them with a flexible epoxy that hardened to give the tape extra rigidity to reduce flexing and provide added strength for the 2 screws. It's a surprisingly stable and shake-free mount.
Here's a side view of the setup:
By using the standard Quest mounting bracket, I still have the ability to rotate the unit side-to-side so my passengers can enter info into the GPS too.
Here's another shot. You can see the power cord and external antenna wire routing down into the passenger footwell area:
I added an extra lighter plug in the area above the passenger's feet (there's plenty of room on top of the black panel down there). So everything is plugged in out of the way (I hated having the power plug in the standard lighter near the shifter...it just seemed to always be in the way. Now its not!)
Best of all, when the unit is not in use, I can slide the entire thing out of the tape slot and into the glove box (and out of view of any wandering eyes). I just notched a little groove in the left wall of the glove box where the wires sit when the glove box door is shut.
It's not the prettiest mounting option, but it works extremely well for me.