i had the same issue to choose between gamma and 430 just last week...i went for Gamma... building my new system on it was a breeze... the points given by Memento should help u choose...
also i should mention a con that i faced which is, that the HDD cage (which is turned) can be a problem if u have multiple HDD and frequently remove them(which I do) as the power and sata connectors fall on the other side of the case...its a minor glitch and shouldn't matter if u dont remove ur HDD... if u do then it can be worked around too... by just plugging them before sliding in and unplugging after sliding out the drive...
check these feedbacks out for more details abt pros and cons: NZXT Gamma: Newegg
plus the rs. 500 that i save went for the extra intake fan that i wanted...
Get either the Cooler Master Blade MAster 120mm fan ( ~ 1K ) per peice, a bit noisy but very good CFM or you can go for a slight comprimise and get the Cooler Master Smoked LED fans ( ~ 450 ) per piece, silent nice ambient glow and decent CFM value and great Value for money, hope this helped .