most desirable are modern apartments within the walking distance to stores, nightlife and public transportation
I wouldn't go so far as 'pick your number' - however they are getting a high selling price - however you will see their sales are slow (although this is compared to the days when things were sold before they were even built, which isn't normal in the rest of the world). I'm not sure exactly where you are thinking of, for example:
Grzybowska 4 - prices PLN 11,800 to PLN 30,000 - about 70 of 240 left for sale
Twarda/Metropolotin - will be interesting, selling from Feb 2012 - prices up to PLN 20,000
Zlote 44 - average price of PLN 30,000 - about 75 of 200+ sold I believe
Platinum towers - bit of a disaster, I think they converted 200 of the apartments into hotel rooms
Opera 2- no idea what they have sold, they don't even advertise, prices up to PLN 50,000/m2 - anyone know the sales success for this project?
I think the safest place in Mokotow, anywhere from the center up to Racławicka metro station.
Warsaw has some similarities to Toronto (in terms of the metro layout) - my understanding is that all the real estate along the metro demands high prices whereas the real estate not along the metro lines goes for significantly less.
Personally (for myself) I would never buy anything not on the metro lines. It costs more but the premium you will recover (of course it will also go down with the market) - reality is I rarely take the metro - but I like to be able to when I want/need to.