They only alt coin I'm interested in is Litecoin at the moment. It's established enough that it can live on it's own. I don't see a need for many of the coins out there. There are some that are pretty interesting such as Namecoin but many just don't need to be there.
Is mining litecoin with my rig which has a speed oh 400kh/s be profitable???
It depends on many things, a few of them:
- Do you need to buy hardware or is it already in your possession?
- Electricity costs of running the hardware (Watts of the rig and $/kWh)
- LTC/$ exchange rate (if you want to convert them to dollars immediately)
- Mining 'wears' the hardware more than running it in idle or gaming for a few hours a day. In other words the risk of failing hardware is increased severely (especially when you running budget hardware, like a cheap PSU or graphics card with bad cooler).