i buy my tools wired. usually cheaper and more powerful. safer too. heard of lithium batteries causing fires and blowing up. i know someone who died in a house fire and it's one of the theories as he had a ton of tools and the fire started in the garage.
if cordless had the same power i'd probably convert but i find wired are so much more powerful.
my drill is wireless though as that is an obvious one you wouldn't want wired unless doing a big job.
It's got to the point now where cordless is as powerful for certain tools. Like Dewalts 57v range. They do nail guns that are as fast as gas powered and can sink 90mm nails into studwork with ease, even battery powered table and mitre saws.
The price is the main barrier, even for most tradesmen at the moment, but I have a feeling it'll get more reasonable as the other brands start to compete.
Regarding the dangers of Li-ions, I think it's a very minute chance of anything going wrong. The same cells are sued in Laptops and other wireless devices. Usually problems arise from incorrect storage, like having the batteries piled up in a toolbox with loose screws and nails etc that could short the battery.
