I can not give you exact numbers. Try to assess them taking into account some facts:
1] Nxt does not require to waste electricity (no centralization of mining power around pro-miners)
2] Colored coins will lead to a revolution in finances (decentralized exchange of property in atomic transactions)
3] Instant transactions (I can't find words to explain how it's cool)
Nxt collected 1,500 USD worth bitcoins. I'll eat my hat if in half a year they won't be worth a couple of millions.
Well, half a year is too short period of time, maybe in a couple of years. Bitcoin required 3 years to go from 5 cents to 250 bucks.
Also these 3 facts r not so awesome.
1. Nobody cares about electricity.
2. Colored coins will be implemented in Bitcoin some day.
3. It's possible to achieve even in Bitcoin/Litecoin with some centralization.