[timytamy]

To echo what others have said, pick a brand (Ryobi/Bosch/DeWalt/Hilti/etc) and invest in their ~18V ecosystem, ie every cordless tool you buy should take the same batteries. Start with a drill and build your stock up from there.

In the event you have a tool that you'd rarely use, (eg we rarely use a circular saw) then it's OK to get a corded version. However, all other things (price/power/durability/etc) being equal, if you can get the same tool that takes the same 18V batteries as the rest of your tools, then purchase the cordless variety.

The thing you want to avoid is having multiple incompatible tools/batteries, it may seem trivial now but down the line it makes management and replacement sooo much easier.