At least, a cell phone on verizon
This started out as a comment on Citizen Smash's blog; his wife was asking for advice on picking out a new verison phone. The advice is based on that company's offerings
Step 1 of cell phone purchasing; figure out how much you want to pay, what you need to do with it, what you want to do with it, what would be nice to have; in that order.
Verizon is a CDMA carrier - the main thing this means is that none of their phones will work in europe or most other countries AT ALL. (they'll work in canada, in some parts of the far east, and I think in mexico). I'm not going into the relative benefits of CDMA versus GSM here; if you want that, go over to the USS clueless archives and search for CDMA and GSM. Mr. den Beste may have a mild bias, but he also knows his stuff. (Nit-pick alert; I know that Verizon has their Worldphone - it's a hybrid device that is very expensive for what it does; unless you NEED the capability, it's not worth the money).
Points to consider:
Do you want a camera on your phone? Cameraphones are generally kinda crappy in image quality, and Verizon has a setup where it will cost you money to get your picture off the phone because you HAVE to use their network to get the picture off. On the other hand, you do have a camera with you all the time, and there is not much moe additional cost to have the camera.
How much non-voice communications capability do you want with your phone? All modern phones have SMS text messaging capabilities, and you can send and receive limited email via SMS text messaging (very limited). Higher end phones can send and receive pictures, sound, and video (clips, not live video calling. Yet). Push-to-talk is a nice feature in certain circumstances, though Verizon's offering is not as fully-featured as Nextel's or Sprint's from what I hear. If you do intend to do a lot of text-based communication, consider that the phone kb is awkward to type on to say the least. I got good at it on my previous phone, but the difference between that and my current PDA phone for text messaging (not to mention email etc) is light-years.
Verizon also has a new service that runs on their BroadbandAccess (aka EVDO) network (available in many parts of the nation including San Diego) called vCast or video on demand. this lets you download short video clips over an on-board broadband connection from various sources. Some people say it's silly, some people say it's a great way to kill 5 minutes at the doctor's etc.
Finally, since verious people have mentioned the PDA/phone converged devices, I'll go into some commentary on them.
The three options with verizon are Blackberrys (verizon carries 3: the 6750 is bare bones and monochrome, the 7750 adds a color screen, and the 7250 is a little smaller, has a lot more memory, and has bluetooth wireless headset capability), the Treo 600, and the Audiovox XV6600 (aka Harrier). The blackberry is hands-down the best device for email integration. It has the best software for this, and an enviable reputation. It is also the most limited in general PDA functionality, and only is a mediocre phone. The Treo 600 is perhaps the best at balancing the trade-offs between PDA and phone functionality, being a better phone than either the blackberry or the XV660, and being a better general-function PDA that the blackberry (Bias Alert - I prefer the Windows Mobile OS to the Palm OS as a general-purpose PDA OS because of it's multitasking capability). The Audiovox XV660 is a PDA first, with a decent but not outstanding phone capability. It is by far the most powerful general-purpose PDA of the three choices, and also offers the capability out of the box to be used to get a laptop onto the internet by functioning as a modem on Verizon's data network. It is a Broadband Access device on verizon's network, with a burst speed capability of 1.5 mbps and a average throughput of 400-800 kpbs downstream when in a supported area, with fallback capability to verizon's slower data network outside of the supported areas.