I’ve definitely heard of Litecoin but my money and mining equipment is focused entirely on Bitcoin at this time. I look at Litecoin as possibly being the future “silver” to Bitcoins “gold”, but at this time it is still more profitable for me to mine Bitcoins.
I may change some rigs over to Litecoin once I get my ASIC’s in, but that all depends on the market at the time. You don’t necessarily need a special rig to mine Litecoins as it can be done on any computer that is already GPU mining, but at this time it would not work on many FPGA rigs because they generally do not have enough RAM and mining Litecoin is RAM intensive.