I see almost everyone here has a portable drill.
I used to have a Black&Decker 9.x volt.. BLAH..
I am now looking for a new one.
What kind do you guys have?
And also, does the drill being 18volt make a difference in the strength and power output that I REALLY need?
The voltage AND chemistry of the battery make a difference. Li-Ion is the way to go in my opinion. Li-Ion gives you full power till the very end of battery life, not a slow drain like older Ni-Cad battery packs. If you are looking to build a cordless tool set from scratch, consider a brand where one battery is interchangeable between many different tools. I use the Ryobi One Plus 18 V series. I have both the drill driver and the impact driver and couldn't be more satisfied with them. I also like the fact that I can use the same battery on most Ryobi tools. It even powers my weed trimmer and hedge clippers. Pick a brand who's price range is in your budget and needs. Personally, carpentry/woodworking is just a hobby so I only use my tools on weekends, so Ryobi suits me just fine. If I did it for a living, I may invest in a Dewalt, or Rigid or a higher end model. All depends on what you want to spend and how often you will use the tools.