Hey Ice,
Concur with the rest here. Especially for starting out, FSX can really be a great introduction to real world flying. As you get more experienced, there may be value in more complex additions to the sim. But even relatively stock FSX can still be useful for the simplest of things like getting comfortable with the layout of an unfamiliar airport or flying a complex approach.
The one caution I'd give you though, if you intend to use FSX for real world flying, is to use FSX as a
Supplement for real flight training, rather than a substitute for it. I don't mean that I think you are going to try to go take your private pilots exam after having only flown FSX (you can't). But if you try to fly a lot of "real world" flight training in FSX without any sort of guidance from an instructor, you can definitely develop a few bad habits that will be hard to break...depending on how wedded you are to them.
Here's a simple example. The FAA Airplane Flying Handbook says that for basic VFR flying, you should spend 90% of your time outside the cockpit and 10% of the time inside. But in flight sims, it's so much easier and endlessly tempting to fly off the instruments. That's going to be a hard habit to break. And failing to do so will not only make you a poorer pilot, but also a potentially less safe one since your primary VFR collision avoidance instruments are located to either side of your nose.
Understand, I am totally not saying that you should shoot your computer to avoid learning any bad habits from it. I'm just saying that, if you intend to use FSX as a tool for learning to actually fly, it will be more effective to learn from an instructor that it's "pitch, power, and trim" (and practice that in FSX) than it will be to learn from FSX that it's "power, pitch, and trim" and then be forced to break the habit.
After that though, and with your choice of add ons, there is virtually no limit to what you can learn from FSX. I've used FSX for everything from practicing my 737 cockpit flows to practicing my low altitude dive recovery rules with the HUD. FSX is a great sandbox in its adaptability.
As for the voice comms, even if you don't hook up with virtual controllers like VATSIM, the stock FSX ATC does a pretty good job of giving you appropriate voice comm for basic things like clearance delivery, taxi, takeoff etc. In real life flying, the secret of understanding what a controller is saying often depends on knowing what he is supposed to say.
Any IFR pilot knows the IFR clearance mantra like some kind of Indiana Jones Temple of Doom chant...
"Callsign", you are cleared to the A airport, via the B departure, then as filed. Climb and maintain C thousand feet. Expect D thousand ten minutes after departure. Departure frequency is E. Squawk F.
Deacon
Oh, at the risk of making a long post longer, I for one am planning to get the A2A C172 when it comes out to help me with MY currency since I haven't flown a light plane in many moons. If it's half as good as their other products, it'll be the best light civil in FSX.