If you're going to buy any power tools at all, buy a high-quality cordless screwdriver with an extra battery; the setup should allow you to charge one battery while working with another. Some of the cordless tool sets out there are very good. A cordless recipro-saw is more useful than a cordless jigsaw. I have a cordless circular saw but usually I'm using the heavy-duty corded model when I need a circular saw. Don't wait to charge and maintain your cordless tool batteries -- get that done before you need to use them. If you can standardize on a single type of cordless battery, you'll be glad you did.
1+ on all of the above.
with rechargeable tools - i learned the hard way. the sears instructions clearly stated (who reads that stuff anyway? well, me now) that the battery should
not be stored on the tool as it would apparently continue to discharge slowly. well, i did. there was no other space to store the batteries in the case that the tools came in - so it made sense to store them there. within a couple years both batteries would not hold a charge and i had to buy new ones.
lesson - the cordless are great, just don't store the batteries on the tools. they will hold the charge for surprisingly long time.