You can count me as one that finds the stock antenna good for my needs. I have a variety of systems, all across the band range and purchasing an antenna for a specific band and foregoing reception on another makes no sense. The all band after market antenna looks a little long for my needs, but that's more of a personal preference.
You seem to me caught up in the "gotta have it" mode even before your SDS100 arrives. I suggest you learn how to program it, learn it's functions and before you start buying all these accessories which you might not find the need for, give it time.
I've owned my SDS100 for 3-1/2 years now, it shipped with the thin battery so that gives you an idea of how long I've owned it and use it daily. I was sent the larger battery and keep the thin battery in a drawer and charge them in the scanner, so no need for an extra battery and charger. I'm still using the original thick battery that Uniden shipped to me free of charge, so that's going on 3 years now. If in the car, battery gets low, I have a charger in my glove compartment next to my rarely used other chargers.
Get the scanner, learn about the scanner, so you're not one of those "how do I scan after hold" type of questions. Basically, take it easy on all the extras for now, you might found out you don't "have to have it" later on. It's a handheld scanner, has it's limitations as they all do, which you won't overcome.