I would suggest Supercoin or Myriadcoin. Both have a TON of potential. I have a very large amount invested in SUPERcoin. It's technology is better than all other anon coins and it is so cheap right now. Buy for 500 satoshi and eventually it could be $1 or $10 per coin. Read, read, read... talk to people, study the charts, make a decision based on the information and you'll do just fine.
There isn't a single coin out there that can outdo Bitcoin, no reason to think any existing coin can overtake Bitcoin's spot, therefore, no reason to think there will be a x1000000 whatever price explosion like Bitcoin had. You could get some cash out of alts, but not rich, unless you hit a really lucky scenareo as greatle described by poster xmasdobo.
Anybody can make 20-30% in a month. Not sure what your definition of rich is, but if you invest 100k and you are making 20% or 20k, you're doing very, very well...so not really sure what you are saying
So someone may be able to have 100% and earn 20% on their investment but they would not be able to earn 20% on the entire 100k