Here are some answers tailored to you...
Page Plus:
This company buys service off VZ in bulk and remarkets it to pre-paid customers through Independent Retailers. In this choice you can continue to use your current VZ Droid handset so there is initial savings there. When/if that current handset breaks you will need to buy another used VZ handset either from an independent retailer or CL/ebay.
$29.99 gets you 1200 minutes / 3000 text / 100MB data.
http://www.pagepluscellular.com/Plans/Talk%20n%20Text%201200.aspx
$55 gets you unlimited talk and text with 500 MB of data.
http://www.pagepluscellular.com/Plans/55%20Plan.aspx
Sending pictures through the cell towers is a huge hog of data so you would need to wait till you got home and swap the card or do it at home via wifi. If you were to go with this plan you would need to switch to wifi whenever possible.
Pro:
VZ towers so no change in coverage for you.
Use existing handset so no investment there.
Con:
You will need to be mindful of data usage.
If you use too much data it does not cost more but rather the plan is for 30 day or 500MB whichever comes first so if you use all the data in 20 days you will spend 10 days unable to move data - at all.
Coverage:
http://www.pagepluscellular.com/Why%20Page%20Plus/Coverage%20Map.aspx
Find a retailer here:
http://www.pagepluscellular.com/Why%20Page%20Plus/Store%20Locator.aspx
Since you will be using your exisiting equipment it will be best to purchase this at a store who will get everything activated.
Metro PCS:
In your area of Florida, this smaller company has service. Florida is one of the markets that they have a dominate stance in. In total they only have about 7 markets nationwide. When and if you leave their market (and their towers) then this company borrows service from Sprint mostly as well as borrows from a few other companies as well. This borrowing does not cost you more - all included, but limited to maybe just text with no talk.
Be sure to check the coverage to be sure it meets your needs and expectations.
http://www.metropcs.com/coverage/
You may be able to continue to use your existing handset here (check with a retailer.) If not the $149 HTC Wildfire is a good vlaue of price and capability.
Monthly service is $40 and that gets you Unlimited talk /text and data when you use a Metro PCS tower (shown in dark purple on their map.
Light purple gets you text only (NO TALK CAPABILITY at any price.) The criss-cross areas give you talk and text but no data.
Where their map says "future expansion" that means they have zero capability there today.
Map: http://www.metropcs.com/coverage/
Pro: Least expensive to use but you will likely have to one time buy a new handset for about $150.
Con: For that savings you are accepting a smaller area where the phone works but if that meets your needs then the saving is a value to you and the way you use a phone.
Boost Mobile / Virgin Mobile:
These two services are wholey owned by Sprint. They are the prepaid side of Sprint. They are marketed different where Boost focuses on all inclusive fro $50/$55 and Virgin focuses on less talk and more data starting at $35. Virgin does have a all inclusive of $55 as well.
For you I would recommend the $55 plan with either. If you can stay under 1200 minutes, Virgin does have a $45 plan that gives 1200 minutes while still getting unlimited text and data.
http://www.virginmobileusa.com/cell-phone-plans/beyond-talk-plans.jsp
The coverage is identical for both and is Sprint towers only:
http://www.virginmobileusa.com/check-cell-phone-coverage
Not bad in your area but study the map above because if you are standing outside the green area you have no capabilities at all.
If you go with Virgin, the best value handset is the Optimus.
http://www.virginmobileusa.com/cell-phone-plans/beyond-talk-plans.jsp
The mspr is $129 but if you keep an eye on Best Buy, Target and Radio Shack, you will often see this handset on sale for $99.
Boost's bargain handset is the $149 (as low as $129 at same retailers) but it is quite a bit more stripped out compared to the Optimus.
http://www.boostmobile.com/shop/phones/
No, you can not swap handsets between Boost and Virgin even though they are ultimately owned by the same company.
One advantage to Boost is they have a shrinkage thing where your monthly goes down by $5 for every 6 months you have been with the company.
Pro:
Unlimited talk / text/ data off any Sprint tower anywhere in the US.
Con:
Must buy handset. ($99-$200)
No borrowing so therefore if sprint does not own a tower there then it just does not work at all.
Straight Talk:
This is a Walmart only offer. The parent company is TracPhone and this is only sold as serviced at Walmart. The reality is that TracPhone bulk buys service from Sprint for the Android offer and remarkets it. The handset is identical (but not swappable) to the Boost handset. Boost charges $55 per month, this charges $45 and the coverage is identical.
http://www.shopstraighttalk.com/bpdirect/straighttalk/PhoneDetails.do?action=view&...
Pro: If Boost is a good choice for you this gets you the same thing but cheaper by $10 right away.
Con: Walmart only - if that matters to you.
T-Mobile:
http://prepaid-phones.t-mobile.com/monthly-4g-plans
$50 for unlimited talk text web
Handset:
$179 for Optimus
http://prepaid-phones.t-mobile.com/monthly-4g-plans
Coverage:
http://prepaid-phones.t-mobile.com/prepaid-coverage
Pro: Coverage is pretty good.
Con: Buy handset which is a little more expensive.
-John