OK, there seems to be a lot of confusion about how this voice/data thing will work. I'm hardly a definitive expert, but having had a Droid and then a Droid Incredible on VZW over the past year, I thought I'd lend my experiences:
Voice takes precedence over a call. It doesn't matter what you're doing. If I'm browsing the web, streaming music or video, downloading apps, or using data in any other way when I get a phone call, the data connection is dropped and the "incoming call screen" pops up. After I'm finished talking (or ignore the call), the phone automatically reconnects to the 3G network in a few seconds. If the webpage/app wasn't fully downloaded when the call came through, this usually means I have to reload.
No idea what's up with the guy whose friend got data and voice on a boat with no WiFi. Either the guy in the boat was only browsing cached webpages, or he was connected to wifi without realising it, or he was using a VOIP app to make the call, or he was toying around with his buddy. Or he's on T-Mobile and not Verizon. No current CDMA phone supports voice/data at the same time on Verizon.
Regular SMS (through the carrier) does not count as data, so you can still send/receive those during calls. Sending/receiving SMS does not disrupt your data connection in any way. I believe this is because SMS piggybacks over the phone's communications to the tower, so it only uses connections that are constant anyway.
I don't use MMS enough to know how they work, but I have read that a data connection is required to send/receive them. Seriously, though, it's 2010. Just email the pictures already.
Other SMS apps (like Google Voice and all those free texting apps) do count as data, so those will come through when you hang up.
Voicemail notifications do not count as data. If you ignore a call while on another call, you'll still get a voicemail notification. Checking your voicemail counts as voice if you dial in to check it. Not sure how it works with VZW Visual Voicemail.
Push notifications for email, package tracking, sports scores, etc. do count as data, and won't go through during a call. On Android, they all arrive almost immediately after you hang up. I have no idea how iOS's notification system will handle this.
Google Maps/Navigation use both data and GPS, and caches the map data for your entire route when you first start navigating. If you lose the data connection while driving, the GPS chip stays active and the navigation app uses the cached map data. If you stray from the planned route while on a call, it can usually get you back on track without a data connection as long as you didn't miss your exit by ten miles or something.
This means if you have a navigation app with its own map pack (like TomTom), this won't be a problem. Note that these apps are usually around 2 GB due to the size of the map package. If you have a navigation app that's about 3 MB, chances are that it uses the data connection to download map data on the fly.
If you're connected to a WiFi network, none of this applies. You still stay connected to the internet during phone calls. This doesn't help those of you who are salivating over the prospect of replacing your cable modem with tethering, but it should hopefully eliminate this concern for anyone who spends any amount of time around WiFi.
Also note that this has only been my experience with Android; any of this could be different on BB (except for SMS).
Regarding 1X: I almost never see 1X data, and I do a lot of traveling around the Midwest and East Coast. The only time I consistently see 1X for extended periods of time is in the basement of a building built in the 1930s, and nobody (on any carrier) can make or receive calls from there anyway.
No. Phone calls take precedence over data. Your functional experience (Pandora/Rhapsody pauses upon incoming call, resumes upon hangup) would be identical on a CDMA iPhone. Text messages always go through no matter what, unless you're using a third-party texting solution. See my post above.
This stopped being true about a year and a half ago. Unlimited data on Verizon is, at least for now, truly unlimited. They may take a close look at individual accounts that use absurd amounts of data (and we're talking like 20GB/mo here), but there is absolutely no automated response to high data usage, and nothing magic about the number 5 GB. None. Zip. Zilcho.
You might be thinking of T-Mobile, who does exactly what you describe.
