I’m starting to get into the DIY home thing and feel it is time to start a tool collection....
I’d prefer to stick with one brand so I don’t have to have 50 batteries laying around associated with this and that company— so having one brand where the batteries are interchangeable is ideal.
There’s several companies
Milwaukee
DeWalt
Makita
Ryobi
Rigid
For those that are handy what are some of the companies you recommend and what are some of the tools you have and feel are must haves ?
The brands you've picked there are basically the best for DIY/homeowners. I'd definitely go with something that is at least 18V because that's going to open up a wider variety of tools. Those brands are all sufficiently good that it might come down to which one is on sale, so maybe price out the tools you want, read some reviews, and make your move at the 4th of July sale.
As far as which tools to get, here's the order I'd go in if I didn't have anything:
1) Cordless drill. That's pretty much staple everyone should have, and you probably didn't need to be told that.
2) Good socket set.
3) Oscillating tool. I just recently got my first one, and I'm kicking myself that I didn't get one years before. They give you the ability to make all sorts of cuts in tight spaces like a pro, and really simplify some jobs. They have interchangeable heads for cutting wood, metal, sanding, etc.. They're the tool you never knew you needed until you have one and realize everything they can do.
I'm not a big fan of Harbor Freight power tools because of durability -- I'd definitely go with one of the brands you have listed above for a new system -- but they do have a really cheap oscillating tool that will give you the basics. Most oscillating tools run $100+ --some substantially more -- but Harbor Freight's is like $30. Even if you burn it out, you're still going to get some use from it. But it's corded, so that's a bit of a limitation.
4) Bench vise. If you're doing DIY crap around the house, the vise is that extra pair of hands you will sometimes kick yourself for not having. You only have that extra pair of hands at the bench...but it is still better than not having it at all. That's something you can get at a great price at Harbor Freight.
5) Circular saw. I use a corded one, but if I had a higher-powered cordless system, I might try one of those.
Depending on what you're doing, the two bench-type tools I'd go for first are 1) radial saw, and 2) table saw. I use my radial saw (it was maybe $70 or so) a lot more. Table saw is really more necessary for longer cuts that most of us home hackers don't use as much. But if you're installing your own flooring, etc., it's essential.
ETA: I've done flooring with just a circular saw rather than a table saw, but I wouldn't recommend it. Massive pain in the ass.