Also, be really honest with yourself about what you want to do with your mobile device(s). By that I mean list what you are realistically going to do with this device. I used to be a major gadget freak - tons of computers and gizmos all over the place. I hardly used half the stuff I had and it was kind of a burden dealing with all the crap that I owned. I've been working on consolidating all of my gadgets lately; I've learned that the first thing you'll want to do is list what you actually use. You said you carry around the following:
Cell phone
PDA
GPS
Camera
Flash drive
For starters, I would combine the cell phone and PDA. There are plenty of Smartphones out there that will meet your needs, whether you like Windows Mobile or Palm. The Treo would be a good choice for you if you want to go with Verizon. Blackberries are also good. What do you use your PDA for? Personally, I wanted a phone with just a few extra features so I got a Smartphone instead of a PDA phone (no touchscreen). I'm currently using a Motorola Q. My primary goals were (1) phone/contacts, (2) good calendar, and (3) Google Maps. The Q did all that in a size that slides into my shirt or pants pocket very easily. I also wanted a few extra features like alarms, lists, notes, and so on.
Regarding GPS, what GPS do you have now? How do you use it? I am planning on getting the new Freedom Bluetooth GPS unit that attaches to your keychain for my Q to use with Google Maps. I've tried out a number of GPS systems and decided that Google Maps was my favorite way of getting directions. Paired with a GPS receiver it would be perfect. I also really like the Garmin Nuvi series, but I don't drive enough to justify spending that much money on a dedicated GPS unit.
As far as you camera goes, I would pick up a slim point-and-shoot like a Canon Digital ELPH. Cell phone cameras stink, period. Even my Q's camera isn't that great. Do yourself a favor and get a good, slim digital camera if you really want a "real" camera. Casio and Nikon also make some good slim ones. Here are some links to get you started:
http://www.usa.canon.com/consu...dexAct&fcategoryid=113
http://www.casio.com/products/Cameras/
http://www.nikonusa.com/template.php?cat=1&grp=2
If you are using a USB flash drive, I would recommend keeping that. I have a nice 2-gig model that has a keychain attachment so that I never lose it. They come in so handy and you can use them on any computer that has a USB port. They come in up to 16gb sizes now, too.
One option you might want to consider is an iPhone. It's expensive, but if you're really going to consolidate your gadgets then it's not nearly as bad as buying separates. I believe it is going to have a 2-megapixel camera on it, which isn't too horrible assuming it takes decent pictures. It offers easy Internet access, email, an iPod, Google Maps (which I'm sure you'll be able to pair with a $99 Bluetooth GPS), and so on. The iPhone is probably the best all-in-one device in existence.
Alternatively, a Smartphone plus an ultraportable laptop may be the way to go for you. Verizon's Unlimited Data EVDO plan for Smartphones gives you 5 gigs of transfer a month and it's easy to hack your laptop to use your phone as a modem.