well dont go buying gpus to mine on now (unless you are sure you can resell them in a couple of months when the market gets flooded) unless you can get 2nd hand real cheap
mine on ATI HD GFX cards you already own - sure
or build that awesome gaming rig and mine on it till no longer profitable and enjoy great gaming for a while to come
Even established miners are finding this a troubling time to forecast the future
Many have bought next generation hardware that will not be delivered for possibly several months
Others will be pulling out of mining when their GFX cards are no longer viable
No-one actually knows what will happen over the next few months,
there never has been a cryptocurrency halve its reward before,
no cryptocurrency has had an increase in the magnitude of hashpower ASIC will bring to Bitcoin,
At best you will get opinions - and they will vary widely
good luck with it