Someone on here wrote up a comparison between all the Baofeng radios.
The UV-B5 (according to them) was the best of them unless you really needed the extra 1 W of transmit power (true 5W vs 4W for the B5) from the UV-82.
Now the UV-82 does have one nice feature the other Baofengs don't. There are 2 transmit buttons, the top one for what's in the top part of the display and the bottom one for what's on the bottom of the display. I don't recall right off if the UV-82 actually has 2 VFOs or not (meaning you can listen to both the top and bottom freqs at the same time). I will assume (and you know what that means) so because the secondary transmit button would be far less useful without it, but I don't recall at the moment.
I'd go with the B5 for my first radio and only get the 82 if you've having problems hitting repeaters or other distant contacts, and that only after getting a much better antenna (I'm assuming, based on your previous threads, that you'll be putting a mag mount antenna on the vehicle you're riding/listening in).