Unless you are in the market for a camcorder recently, you might not have noticed but it's gotten exponentially more complicated to buy a camcorder. Now you have camcorders which record on flash memory cards, internal flash memory, hard drives, traditional MiniDV, cd's, dvd's, and even hybrids of these devices. They've also exploded into a ton of different form factors, from the FlipVideo camcorders, to hand helds, even digital SLR's like the Canon 5D Mark II or Nikon D400 support video.
Which one should you buy? Well that depends on a lot of factors, but I generally think that the flash memory camcorders provide the best combination of battery life, durability, expandability, and several other important factors. As for the form factor, that really depends on what you view to be the most common way you use your camcorder. If you travel a lot, the smaller flash camcorders are a good bet. If you a photographer first and a videographer second, then the Canon 5D might be the best fit.
How do I know for sure? I'd recommend you read some reviews, at The Camcorder Review (www.TheCamcorderReview.com). It is a great site that can provide more insight into the camcorder options available today.
