Hey K, that is most of it. Probably the main thing missing is a charge controller. In most solar/battery applications, there is a device called a controller that does 2 things. First, if keeps the solar panel from overcharging the battery. This can happen on a sunny day when the battery is already full. Second, it does not allow the battery to back feed into the panel at night, which can happen. In this case, you drain the battery and damage the panel at the same time, very costly.
If all you want is 12 volt electricity, I would scratch the inverter off the list, it is only designed to convert the 12 volt power to 120 or 220 volt AC power for the home or small appliances.
As far as the controller goes, you have another option. If you are using a battery for storage, and its Amp Hour rating (AH) is at least 50 times what the panels maximum current (amps) is, then you do not need a charge controller. The reason for this is that the panel is considered to be a trickle charger at that level, and can never harm the battery, even if you have a full battery and a week of clear sun.
If you are a handy guy and want to do this yourself, here is my suggestion. Get either a heavy duty deep cycle 12 volt battery, the kind someone might use for a camper or RV, or to run an electric trolling motor on a fishing boat, or invest in a pair of golf cart batteries. Trojan T-105 are the best, but cost about $90 USD each. You would need a pair because golf cart batteries are always 6 volt, and panels and most small electronics and inverters work on 12. The good news is this type of battery is rated at 220 AH, so you can run up to a 75 watt panel directly into one without a charger controller. We have a set up like this in our home, and the 12 volt DC power is used to run LED cabinet lighting, a small fan, nightlights, our phone answering machine and a portable radio all on 12 volts. They work even if the main power is out because the battery runs them, and the panel keeps the battery charged. There are probably other 12 volt items you can run on your little system as well. The only important things to remember once you have a panel, diode or controller, and battery, is the polarity must be correct, meaning the positive from the panel must go to the positive of the battery, and you need to water the battery once a month or so, more often in hot weather. Charging causes electrolyte to vaporize, which slowly drains the battery of water. All you have to do is add enough distilled water to the battery cells once in a while to keep them full.
If you decide not to use the charge controller, then you will need a diode. A diode is an electrical check valve, allowing current to flow in one direction only. These can be purchased at Radio Shack for less than $1, but most panel manufacturers install them in the junction box in the back of their panel free of charge anyway. Once you get your panel, diode and battery hooked together, you're making your own energy, just try to use it juriously, don't waste it on car headlights and other high use devices that will simply run your battery down needlessly. Good luck K, and take care, Rudydoo
Home Power Magazine, Homepower.com
The Complete Battery Book, by Richard Perez, library