If you are using rw weather, FSC is able to show this data when you enable the weather downloads. Since FSX does the same, the chances are high that both programs match on their data input.

Now the problem arises if there's a different data set or if you have more options on the runways in use. This could be a parallel runway situation or one where every available one will have the same amount of crosswind. You can't really predict the FSX ATC decision, unfortunately.

With an external weather program, there often is a flight plan option to import plans and catch a glimpse on the weather data before running FSX itself. However, when using FSX ATC, the same situation may arise. No precise prediction possible.
You could use online ATC or some addon software to counteract this. I think RC4, PFE or VoxATC are more predictable and/or able to offer some more takeoff options.
Perhaps the hard way in FSX would be to just take off on the runway you prefer and later enable the ATC or something. I haven't tried, but that's what I would do if the program is to rigid on choosing the right runway.

If you have special airports where they take off with a certain amount of tailwind and only switch if this amount reaches a certain limit, the default ATC won't be able to cope with that. The rw operations sometimes run that way to keep the noise abatement routes intact unless the safety is severely affected with heavy planes taking off/landing in tailwind situations for example.
So you may see some major hubs working in the wrong direction until e. g. 5 kts of tailwind on the active is exceeded over an amount of time. The actual limits depend on the airport of course and the planes taking off or landing also have some manufacturer and/or airline limits they operate within.

Nice video on a 'too much tailwind decision'. Bad ATC guy, telling wrong values. http://www.youtube.com/watch?v=36g83GkG1eU

That's because there is none with the default ATC. REX allows a closer look in the conditions with the flight planner, but you may still see FSX picking other runways than expected. 

Ok, thanks for feedback guys.
Anyway it's always interesting to know about how other simmers manage their ILS flights!

In general I fly my ILS flights, obviously, according to the flightplan implemented into the FMS - However, anytime the ATC orders me to takeoff or land on a certain runway or change altitude I always let them overrule the the original flightplan (I hate to hear them yelling at me!)

Until reaching T/D I stick to my fligtplan regarding to course and altitude and let the AP do the job. Apart from the final cruise altitude, ATC always has another idea of the transition altitude which then force me to turn of my VNAV and turn it on again when the altitude again corresponds to the readouts in the FMS.

After T/D I simply let ATC take all further decisions - that is, the transition altitude, course and the runway for landing. When the ATC gives med the final runway data I put frequency and course into the FMS, hit the APP button and then go for Autoland while closely monitoring the flaps setting schedule on the FMS (among all the other stuff!). Then AP off at 200 agl.

So in practice I only need to predict the takeoff runway in the way I fly my ILS flights.

I wonder how much different you guys fly from this? 

The thing is, that I actually like the fsx ATC folks and their voices (!) and I don't fancy to argue much with them! 
 
     

Me says that the way people are flying their sim is as different as the way people install their software. Very little chance of finding two guys doing the same thing.

I'm either on online ATC, very rarely with VoxATC and most of the time in complete silence. Other times I let the rw live ATC run in the background, which I also see as silence since I don't have to talk there.
I think MS did a nice job on offering a sort of ATC impression, but it isn't more than that and I later found it to be a problem since it establishes a lot of bad habits and acts too static when you want to fly certain locations and approaches or even planes (Concorde in cruise climb). The voices are good though, although you soon have heard them all.

The live rw ATC thing is really funny at times, very boring at others. Same as online ATC.  Now the live stuff may train you on listening to the folks and also gives a ton of input on 'lets look that up things'.

If I could recommend anything, I'd say that one should get rid of the default ATC as soon as possible. Listen to the rw folks and try to understand what they are doing and flying or find a nice online ATC spot with good coverage and go from VFR flights to IFR ones, like a real pilot would do.

We should be aware that most of us learn their stuff backwards and, when only using the MS ATC, also wrong in certain aspects. It really is a challenge but also very rewarding to try a closer to real approach, learning small planes and VFR first, then stepping up.

So if I want to enjoy some scenery and/or plane, there's silence, no ATC needed. If I want to have some thrill when flying a boring FMC plane, I pick the online ATC and a denser area. You never know what's coming and your confidence on flying alone is soon replaced by a sort of stress. Very funny at times, even without system failures or something.

Maybe try the live ATC feeds around the Net. http://www.liveatc.net/ Tons of locations there and if you are flying with rw weather in the sim and listen to them, the regular approach paths will be the same.
It may also teach a bit on the language thingy, while you can enjoy your flights in FSX without the default ATC nagging you about weird things to do.