On the topic of power meters, a power meters is IMO the best thing you could invest in other than the basic stuff such as a bike that fits, if you are serious about doing as well as you can and/or making the most of your time.
Training with power data is a revelation, there is nowhere to hide and you can not kid yourself about how hard you are working. But, they cost a lot (power2max is the cheapest proven crank based pm I believe, the power tap basic model is about the same price, both have advantages and disadvantages, Quarq and SRM cost a lot more) and the amount of information and different ways to interpret the data can be overwhelming. Not everyone can or wants to invest this much money in one. It can, on the face of it seem like you are spending a huge sum on not much (you could buy a pretty great bike or some very nice wheels for the price of a power meter) but the benefits in use are great. I love my power meter and could not imagine training without it now.
I wouldn't worry about "missing out" though and you can train VERY effectively without one.