ARI- I would recommend you not even debate with those athiests. If they are Jewish you can show them the video "divineinformation" at
http://www.divineinformation.com/downloads/default.asp or many of the other videos here and at Torahanytime.com .
If these people tell you that after
they die they wont exist, you can tell them that they are probably right in their case, but for you, you see and hope a future for yourself, so when you see people partying and "living it up" theirs nothing to be jealous about. If those people are Jewish you can try to direct them to the right path, but if you see that they have a negative affect on you, then its best to just seperate with them and not hang out with them anymore.
This Shabb-t, for some reason this line came to me and I was thinking about it, now I know why partly (to show you
) . after Lecha Dodi we say the paragraph of "Mizmor Shir Leyom HaShabb-t. it says
" A fool does not realize, and an unwise person does not understand this (i.e. the following:) When the wicked bloom like grass, and the evildoers blossom (i.e. when they seem extremly successful), it is to destroy them forever (i.e. they are rewarded for their few good deeds in this World, and they will have no portion in the World to Come!)