I have two sets of DeWalt tools 1 18v NiCad and 1 12v Li-ion. The 18v are the major tools and the 12v are an impact driver and drill set.
From friends and family's experience, it really is you get what you pay for (with diminishing returns)
The inexpensive Royobi-tier will be fine for a home owner who uses them once or twice a year.
Pretty much any Milwaukee/Rigid/Mikita/DeWalt-tier will last stand up to frequent use for years to come. One brand might make a better saw, another a better drill, and still another a better sander; overall they are probably comparable.
Then there is the festool-tier which are great tools, cost twice as much as the tier below and, in my opinion, beyond the point of diminishing returns.
I got my 18v set back in 2008 and picked it for the slightly better drill (according the reviews), I got my 12v set in 2012 and I picked the tools based on which ones fit most comfortably in my hand and felt the most balanced.
Buy a set to start, in many cases its cheaper to buy the set than to buy each tool.
Once you have picked your price-point, pick whichever color you like best; personally in all power tools I default to DeWalt, Bosch, and Makita, but I also have rigid, harbor freight, porter-cable, and delta in the shop.