I guess in general it comes down to the percentage of time spent transporting the bike vs. time spent doing other things. A perfect bike-friendly vehicle would be something like a full-sized minivan, where you just toss the whole bike in the back, maybe with some padding over it for protection, or a few simple tie-downs, and go. As a bonus the bike is protected from the elements and theft. From there you work you way down to various levels of disassembly of the bike, and reconfiguration of the vehicle (folding or removing seats, moving cargo around, etc.). And finally you get to external racks which work with just about anything on 4 wheels. So you have to balance convenience vs. what you're sacrificing for all the rest of the time that you're not carrying a bike.
So, if you're only transporting the bike once or twice a week, all the rest of the time you're still paying the "bike tax" in MPG and other factors, which is kind of ironic if you think about it. I took the Thule roof rack off my Camry because it was noisy and noticeably reduced my fuel mileage. It was convenient for the one time a week or so that I used it, but the other 6 days, including my LONG work commute, it was a burden. Plus if you thought a Camry couldn't get any uglier, you haven't seen one with a Thule rack
. I now mostly just use a trunk rack, though it blocks my access to the trunk and has some problems rubbing on the seat tube. I'll probably try a hitch rack at some point, though it will have to be on my next car as the Camry is about ready for the junkyard and any new small car will probably have warranty issues with installing a trailer hitch.