Raspberry PI.
0.3 kh/s is the current top end I've seen coming from the pi.
So if a pi costs $50, and a LTC is $0.07, that's 714 LTC/pi.
@ 0.3 kh/s and a difficulty of 40, you are looking at 0.22 LTC/month. It would take about 200 years to pay one off UNLESS LTC jumps in price dramatically, which is a likely scenario but.. yea.. raspi not lookin so good until we can squeeze a bit more out of it.
[litecoinpool calculator] [kattare calculator]so a raspi runs at about 2 watts.. well, I have cheaaaaap electricity in canada, and it would cost about a buck for every 20 cents it made. so the raspi is actually the most expensive rig for LTC if you want to earn money.
however I put a few solar panels (3x7w) in my big truck outside and I got everything ready to go to start wirelessly raspiing once my wifi dongle gets here. I was going to monitor the temp of the truck all day just for the sheer curiosity of it all, but if I can mine in the idle clocks on the raspi at the same time, maybe throw a couple more pi's in there, set them to payout to a separate wallet and just leave it for all eternity, man, in 20 years, 1 LTC could be a lot of money, who knows maybe buy a new truck paid for by solar pi's.