Singles are good on lakes -- No matter which way teh wind blows, you will get to shore. On BIG lakes, and the ocean, if the wind or tides are going out, you better have a big lunch with you if you are thinking you want to still be alive when you get to the next shore line. (Example: any ocean water on the west coast, the next shore west might be Japan more than a days drift.
Twins do not have to share the same fuel tanks, (shouldn't actually) and that may or not help in fuel issues, since they are usually filled at the same time, and same place.
Twins offer a very high degree of maneuverability over a single and kicker.
Twins offer double redundancy.
Twins keep the mechanics more happy, (yes a slightly higher than a single and kicker maintenance fee.)
The posts so far are very informational, most repetitive of what has been covered here many times over, and reading all of them, will get you information but not make the decision for you. It boils down to waht you want. The good thing; Either will get the job done.
After you get this decision made, try deciding whether you want your boat plug to be an "inny" or an "outty" and look up those discussions. That will keep you going for another 249 hours and 20 minutes :wink sort'a.
Harvey
SleepyC :moon