LTC, unless I really really trust a third party and do offline transaction with BTC
For me BTC is too slow for every day life even if it changed the world of money.
This again?
Have you actually used BTC to purchase something. It takes seconds. There's no need to wait for confirmations on low value goods.
I think you meant 1 confirmation is enough?
It depends on how much you are prepared to lose
No, 0 confirmations. To reverse a 0 confirmation BTC Transaction is still more complicated than a CreditCard-Transaction and success is not guaranteed. Also it's not cost free. To do this for the Value of Groceries of a Coffee is ridiculous.
If the BTC are send with the right fee, it's also nearly impossible they will result in a double spend.
I wouldn't sell a car or a house with 0 confirms (I also wouldn't accept CC for that), but a Beer, Coffee, etc. sure. Basically as a shop owner, everything where I'm willing to accept CC for.