Roughly 450 khash/s. I have a 5870 which puts out 280ish khash (which seems low but I can't get it to stay up for extended periods of time). 50 from an i5 2500. And I put some cpuminer's on some stuff at work with a kill script to delete them after a day. Unfortunately the kill script managed to fail on a couple of them and I couldn't find which one's did (they all had the same workerid). So that's running at 100-200 khash depending on the other loads, (the process will stop as soon as they restart the server though.
I don't think the mining can have too much of an effect on the strength of a coin once it takes off. If it exists and people trade with it then it doesn't matter really where the new influx of new coins comes from as long as it isn't all from a single person.
As more people start mining with higher computational power then profitability of mining will decrease because the same amount of coins are still dispersed.
But the vast majority of people who use a currency don't use it because they created it. I mean think of it in terms of say USD. I don't print them but I sure as hell use them and attribute value to them. As long as people do that the currency will hold it's value.
Is the calculator working properly? I've got roughly 450 khash/s and according to the calculator I should be getting ~4.5 ltc a day however I've been running 5ish days and have not been getting those numbers.
If there is a time to invest in litecoins it is now. (or maybe when they take a bit of a dip in value) Mining is more profitable than BTC mining right now.